CN100455345C - Composite heat exchange microreactor - Google Patents

Abstract

The invention relates to a micro-chemical chemical mechanical system for heat transfer, mass transfer and chemical reaction between micro-fluid media, in particular to a heat-exchange micro-reactor integrating multiple temperature regions. The structure has a substrate and a sealing plate, and one or several substrates and sealing plates are combined to form a single-layer structure or a multi-layer structure. There is a microchemical reaction channel and several heat exchange channels on the substrate, and a multi-section heat exchange area is formed along a group of microchemical reaction channels, so as to realize the isothermal operation or variable temperature operation of the strong exothermic reaction process and the isothermal operation of the endothermic reaction process as a whole. Or variable temperature operation and immediate termination of endothermic reactions. In addition, it can also be used as a measurement and analysis tool for the heat absorption (release) of chemical reactions.

Description

Composite heat exchange microreactor

Technical field

The invention relates to a micro-chemical chemical mechanical system for heat transfer, mass transfer and chemical reaction between micro-fluid media, in particular to a composite heat-exchange micro-reactor integrating multiple temperature regions.

Background technique

According to the widely accepted definition of microsystem in the field of chemistry and chemical engineering, microreactor refers to a small reaction system manufactured by micromachining and precision machining technology, and the microchannel size of the fluid in the microreactor is from submicron to submillimeter order of magnitude. For reactions at the molecular level, the volume of the microreactor is very large, so it has little effect on the reaction mechanism and reaction kinetics. The main advantages are the enhancement of the mass and heat transfer process and the improvement of the fluid flow pattern compared with traditional reaction equipment. In the microreactor, the temperature gradient increases rapidly as the line scale decreases, resulting in a significant increase in the heat transfer driving force, thereby expanding the thermal diffusion flux per unit volume or unit area; in addition, due to the reduced fluid thickness , and the corresponding area-to-volume ratio is significantly improved. The strong heat transfer driving force and large enough contact surface area make it easy to control the heat exchange between the reaction fluid in the microchannel and the outside world.

In terms of heat exchange methods for microreactors, oil baths, water baths, ovens or cold boxes used in laboratory devices were often borrowed in the early days. This approach affects the integration of microreactors and system components, and is not conducive to on-line monitoring. Therefore, integrating heat exchange elements into one body has become the development trend of microreactors. At present, in microreactors with integrated heat exchange elements, resistance heaters are generally used on the outside of the micro reaction channel wall or by adding micro heating channel plates to provide the heat required by the reaction zone. By adding micro cooling channel plates Remove heat from reaction zone. However, when the reaction process requires variable temperature operation, in the same microreactor, the above heating and cooling methods are not convenient for combination and packaging.

Scientists from the Institute of Microtechnology (IMM) in Mainz, Germany, designed a more compact integrated heat-exchange metal microreactor by arranging micro-reaction channels and micro-heat exchange channels at intervals on the upper and lower surfaces of the same substrate, and in Presented at the 2nd International Conference on Micro Reaction Technology (IMRET 2). However, this method of alternately arranging microchannels on both sides is not easy to form and superimpose and enlarge the substrate structure. Moreover, when the reaction process requires variable temperature operation, it is not easy to arrange heating channels and cooling channels in the reactor at the same time.

Scientists from the Massachusetts Institute of Technology (MIT) disclosed a silicon-based microchemical reactor integrating three temperature regions in Angewandte Chemie Int.Ed.2005, 44, 2-6, which is heated externally The method of aluminum block and external cooling aluminum block enables heat exchange between the aluminum block and the silicon plate containing the micro-reaction channel, and the silicon material between the heat exchange areas on the substrate is removed by etching, and a medium-temperature area is formed on the same micro-reaction channel substrate , local high temperature zone and local low temperature zone. However, the aluminum block heat exchange unit of the microreactor is obviously not suitable for further packaging and industrial application.

Contents of the invention

The purpose of the present invention is to provide a composite heat exchange microreactor which can simultaneously have the advantages of heat exchanger and reactor in order to overcome the deficiencies of the prior art in terms of manufacture, assembly, integration and packaging. The reactor can release (supply) excess (required) heat in time for the exothermic (endothermic) reaction in the same device, realize isothermal operation or variable temperature operation of the strong exothermic reaction process, isothermal operation or Temperature-changing operation, immediate termination of endothermic reaction; another object of the present invention is to carry out heat balance calculation on the heat exchange fluid, and the present invention can also be used as a measurement and analysis tool for chemical reaction heat absorption (release).

The technical solution of the present invention is: in order to achieve the above purpose, the present invention rationally arranges micro-reaction channels and heat exchange channels on the same substrate, and forms a multi-section heat exchange area along a group of micro-chemical reaction channels in a micro-reactor. High efficiency, fast reaction speed, good selectivity in the reaction process, high material conversion rate, low flow resistance, high structural strength, high temperature and low temperature resistance, small reactor volume, light weight, convenient space layout, easy to expand the number of reaction units, The manufacturing process is simple, easy to produce in batches, and the cost performance is high.

The specific technical solution of the present invention is: a composite heat exchange microreactor, consisting of a sealing plate 05 and at least one substrate 01, the upper surface of the substrate 01 has a microreaction channel 10 and a heat exchange channel at the same time, each channel has at least One inlet and one outlet; the sealing plate 05 is provided with a series of inlet through holes and outlet through holes, and respectively correspond to the inlet and outlet of each channel on the substrate 01; there is at least one set of corresponding The insulation groove 16, 56 can be formed by removing solid material or filling insulation material.

A micro-reaction channel and at least two heat exchange channels are compactly arranged on the upper surface of a substrate 01; the number of heat exchange channels is appropriately increased according to the amount of heat transfer required for the reaction, for example, when the endothermic reaction process absorbs heat When it is large, in order to ensure sufficient heat transfer or uniform reaction channel temperature, the number of heat exchange channels should be increased, but too many heat exchange channel sections will affect the compactness of the reactor. The heat exchange channel is in the micron scale or millimeter scale, the reaction channel is in the micron scale, and the heat exchange channels 11 , 12 , 13 are arranged compactly in sections along with the micro reaction channel 10 in a wave or serpentine form. The hot fluid medium flowing through the heat exchange channel in sections can accurately and efficiently provide the heat required for the chemical reaction to occur; the cold fluid medium flowing through the heat exchange channel in sections can take away the heat generated by the chemical reaction in time . Among the heat exchange channel sections on the base plate, there is at least one heat insulation groove formed by removing solid material or filling heat insulating material between the channel section for supplying heat and the channel section for removing heat. The endothermic reaction process can provide heat by controlling the parameters of the hot fluid medium in the heat exchange channel in the first section, and start the chemical reaction immediately, and maintain the chemical reaction along the optimal temperature curve by controlling the parameters of the fluid medium in the heat exchange channel in the middle section. By controlling the parameters of the cooling fluid medium in the last heat exchange channel to remove heat and terminate the chemical reaction immediately.

The sealing plate that encapsulates the substrate has the same length and width as the substrate, and its thickness is on the order of microns or millimeters. The sealing plate is provided with through holes corresponding to the inlets and outlets of the channels on the substrate and heat insulating grooves corresponding to the heat insulating grooves of the substrate.

After aligning the sealing plate 05 and the base plate 01, they are closely bonded together by bonding or diffusion welding to form a composite heat exchange microreactor with a single-layer structure. The inlets of the single-layer composite heat-exchanging microreactor are respectively connected to fluid chemical substance containers, and the fluid medium flows into the corresponding channel from the inlet along the vertical direction of the plate surface, and flows out of the microreactor from the outlet of the channel along the vertical direction of the plate surface.

The present invention also relates to a composite heat exchange microreactor, wherein the sealing plate 05 is used as a top sealing plate, the substrate 01 is used as a bottom substrate, and at least one intermediate substrate 03 is accommodated in the top sealing plate and the bottom between substrates. Wherein, the inlets and outlets of all channels on the intermediate substrate 03 are through holes, and other features are the same as those of the substrate 01 . After aligning the sealing plate, the intermediate substrate and the substrate, they are tightly bonded together by bonding or diffusion welding to form a multi-layer composite heat exchange microreactor. The inlets of the multi-layer structure composite heat exchange microreactor are respectively connected to the container of the fluid chemical substance, and the fluid chemical substance is distributed from the inlet along the vertical direction of the plate surface into the corresponding channels of each layer, and along the direction of the vertical plate surface, the outlet of each layer channel concentrated outflow. The number of intermediate substrates mentioned therein should be selected according to the output requirements and the flow rate of each fluid substance participating in the reaction and heat exchange, the cross-sectional size of each channel, and the channel length. It should be ensured that each fluid substance fills the channel during the reaction. To ensure uniform reaction residence time, the intermediate substrate should not be too much.

Wherein the substrate, intermediate substrate and sealing plate are composed of silicon, silicon compound, ceramics, metal or heat-resistant glass, or silicon or silicon compound and heat-resistant glass.

The substrate, intermediate substrate and sealing plate described therein are processed by milling, chemical etching, plasma etching, electric spark ablation, laser ablation or LIGA technology.

The substrate, the intermediate substrate and the sealing plate are packaged by bonding or diffusion welding.

For catalytic reactions, the catalyst can be arranged by vapor deposition technology or embedded in porous materials before packaging, or it can be coated on the wall of the reaction channel by slurry technology after packaging.

The invention also provides the application of the reactor in the measurement and analysis of the heat absorption (release) of chemical reactions. By measuring the mass flow M of the heat exchange fluid, the inlet temperature T ₁ , the outlet temperature T ₂ and the mass flow M' of the reaction fluid, the unit time can be calculated by combining the heat balance formula Q'=Q=Mc(T ₂ -T ₁ ) The heat Q' absorbed or released during the internal chemical reaction and the heat absorbed (released) per unit mass of reactant Q'/M'. In the formula, Q is the heat transfer amount of the heat exchange fluid per unit time, and c is the heat capacity of the heat exchange fluid.

Beneficial effect:

1. In the present invention, micro-reaction channels and heat exchange channels are reasonably arranged on the same substrate, and a multi-section heat exchange area is formed along a group of micro-chemical reaction channels in a micro-reactor. The heat transfer efficiency is high, the reaction speed is fast, and the reaction process is stable. Good selectivity, high material conversion rate and low flow resistance.

2. Processing materials and manufacturing methods are flexible, and reactors with high structural strength, high temperature and low temperature resistance can be produced.

3. The reactor is small in size, light in weight, and convenient in space arrangement.

4. Compared with the prior art, the present invention has the remarkable features of compact structure, convenient processing, simple assembly and packaging, easy expansion of the number of reaction units, easy batch production, and more suitable for industrial application.

Description of drawings

Figure 1 is a schematic diagram of the principle of a compound heat exchange microreactor composed of a base plate and a sealing plate.

Fig. 2 shows an exploded view of a single-layer structure embodiment of a composite heat exchange microreactor.

Fig. 3 shows an exploded view of an embodiment of a composite heat exchange microreactor with a single-layer structure viewed from below.

Fig. 4 shows a top view of the substrate of an embodiment of a single-layer structure compound heat exchange microreactor.

Fig. 5 shows an exploded view of a multi-layer structure embodiment of a compound heat exchange microreactor.

Fig. 6 shows a structure diagram of an intermediate substrate of an embodiment of a composite heat exchange microreactor with a multilayer structure.

Fig. 7 shows a structural view of the middle substrate of an embodiment of a composite heat exchange microreactor with a multilayer structure viewed from below.

Among them, 01 is the substrate, 02 and 03 are the intermediate substrates, 10 and 30 are the micro-reaction channels, 10a and 30a are the first entrance of the micro-reaction channel, 10b and 30b are the second entrance of the micro-reaction channel, 10c and 30c are the outlets of the micro-reaction channel, and 11 , 31 is the first group of heat exchange channels, 11a, 31a are the inlets of the first group of heat exchange channels, 11c, 31c are the outlets of the first group of heat exchange channels, 12, 32 are the second group of heat exchange channels, 12a, 32a are the first The inlets of the second group of heat exchange channels, 12c and 32c are the outlets of the second group of heat exchange channels, 13 and 33 are the third group of heat exchange channels, 13a and 33a are the inlets of the third group of heat exchange channels, 13c and 33c are the third group of heat exchange channels Outlets of the hot passage, 16 and 36 are heat insulation grooves on the substrate, 17 and 37 are pin ports on the substrate, 05 is the sealing plate, 50a and 50b are the inlets of the reaction fluid, 50c is the outlet of the reaction fluid, and 51a is the first group replacement Heat fluid inlet, 51c is the first group of heat exchange fluid outlets, 52a is the second group of heat exchange fluid inlets, 52c is the second group of heat exchange fluid outlets, 53a is the third group of heat exchange fluid inlets, 53c is the third group of heat exchange fluid Thermal fluid outlet, 56 is the insulation groove on the sealing plate, and 57 is the pin through hole on the sealing plate.

Detailed ways

The present invention will be further described below in conjunction with drawings and embodiments.

Example 1

As shown in Figure 1, the principle of the composite heat exchange microreactor is shown. The schematic structure includes two parts: a substrate 01 and a sealing plate 05.

The upper surface of the substrate 01 is provided with microchannels 10 for reactants to mix and react, a first group of heat exchange channels 11 arranged with the microreaction channels 10, a second group of heat exchange channels 12 arranged with the microreaction channels 10, The third group of heat exchange channels 13 arranged along with the micro-reaction channels 10 and the heat insulation groove 16 for heat insulation. Wherein, the micro-reaction channels 10 include inlets 10a, 10b and outlets 10c, the first group of heat exchange channels 11 include inlets 11a and outlets 11c, the second group of heat exchange channels 12 include inlets 12a and outlets 12c, and the third group of heat exchange channels 13 Includes inlet 13a and outlet 13c.

The sealing plate 05 is provided with reaction fluid inlets 50a, 50b and outlets 50c, a first group of heat exchange fluid inlets 51a and outlets 51c, a second group of heat exchange fluid inlets 52a and outlets 52c, a third group of heat exchange fluid inlets 53a and outlets 53c, the heat insulation groove 56 that plays a role of heat insulation.

The structured substrate 01 and sealing plate 05 are packaged by bonding or diffusion welding.

The inlets 50a, 50b, 51a, 52a, and 53a are respectively connected to the fluid chemical substance container, and the fluid chemical substance flows into the corresponding channel from the inlet along the direction perpendicular to the sealing plate 05, and passes through the outlet of the channel and the sealing plate along the direction perpendicular to the sealing plate 05 The corresponding outlet on 05 flows out.

The hot fluid medium flowing through the heat exchange channel in sections can accurately and efficiently provide the heat required for the chemical reaction to occur; the cold fluid medium flowing through the heat exchange channel in sections can take away the heat generated by the chemical reaction in time . The endothermic reaction process can provide heat by controlling the parameters of the thermal fluid medium in the heat exchange channel 11 in the first section, and immediately start the chemical reaction, and maintain the chemical reaction along the most The optimal temperature curve is carried out, and the heat is removed by controlling the parameters of the cooling fluid medium in the last heat exchange channel 13, and the chemical reaction is terminated immediately. By measuring the mass flow M of the heat exchange fluid, the inlet temperature T ₁ , the outlet temperature T ₂ and the mass flow M' of the reaction fluid, the unit time can be calculated by combining the heat balance formula Q'=Q=Mc(T ₂ -T ₁ ) The heat Q' absorbed or released during the internal chemical reaction and the heat absorbed (released) per unit mass of reactant Q'/M'. In the formula, Q is the heat transfer amount of the heat exchange fluid per unit time, and c is the heat capacity of the heat exchange fluid.

Example 2

Taking the endothermic non-catalytic reaction process as an example, the formation and application of a single-layer composite heat exchange microreactor embodiment is introduced.

As shown in FIG. 2 , it is an exploded view of a single-layer structure embodiment of a composite heat exchange microreactor, which is composed of a silicon material substrate 01 and a heat-resistant glass sealing plate 05 .

As shown in Fig. 3 and the figure, an exploded view of an embodiment of a single-layer structure compound heat exchange microreactor is shown from the angle viewed from below.

FIG. 4 is a top view of a silicon material substrate 01 in an embodiment of a single-layer structure compound heat exchange microreactor.

The silicon material is removed by plasma etching technology, and the serpentine microchannel 10 where the reactants mix and react is carved on the upper surface of the substrate 01, and the first section for providing heat to start the reaction arranged along with the microreaction channel 10 The heat exchange channel 11, the second heat exchange channel 12 arranged with the micro reaction channel 10 for providing heat to maintain the reaction, and the third heat exchange channel 13 arranged with the micro reaction channel 10 for removing heat and immediately terminating the reaction , the slit 16 which plays the role of heat insulation, and the pin hole 17 which plays the role of centering. Wherein, the micro-reaction channel 10 includes inlets 10a, 10b and outlets 10c, the first section of heat exchange channels 11 includes inlets 11a and outlets 11c, the second section of heat exchange channels 12 includes inlets 12a and outlets 12c, and the third section of heat exchange channels 13 Includes inlet 13a and outlet 13c.

The reaction fluid inlets 50a, 50b and outlets 50c, the first group of heat exchange fluid inlets 51a and outlets 51c, the second group of heat exchange fluid inlets 52a and outlets 52c are etched on the heat-resistant glass sealing plate 05 by wet chemical etching process , the third group of heat exchange fluid inlets 53a and outlets 53c, gaps 56 for heat insulation, and pin through holes 57 for centering.

After the silicon material substrate 01 and the heat-resistant glass sealing plate 05 are centered by pins, anodic bonding technology is used for packaging.

The inlets 50a, 50b, 51a, 52a, and 53a are respectively connected to the fluid chemical substance container, and the fluid chemical substance flows into the corresponding channel from the inlet along the direction perpendicular to the sealing plate 05, and passes through the outlet of the channel and the sealing plate along the direction perpendicular to the sealing plate 05 The corresponding outlet on 05 flows out.

Example 3

Taking the endothermic non-catalytic reaction process as an example, the formation and application of a multi-layer structure compound heat exchange microreactor embodiment is introduced.

Figure 5 is an exploded view of a three-layer structure embodiment of a compound heat exchange microreactor made of 304 stainless steel. It consists of a substrate 01, a sealing plate 05 and two intermediate substrates 02 and 03 with the same characteristics.

The stainless steel material is removed by chemical etching technology, and the same channel structure is etched on the upper surfaces of the 304 stainless steel substrate 01, 304 stainless steel intermediate substrates 02 and 03. Then use the electric spark ablation technology to discharge and ablate the heat insulation gaps on the substrate 01, the intermediate substrates 02 and 03 on the electric discharge forming machine tool with thin brass electrodes. Finally, the inlets, outlets and pin ports of all the channels on the intermediate substrates 02 and 03 are drilled as through holes by electric spark ablation technology.

The forming process will be introduced below taking 304 stainless steel intermediate substrate 03 as an example.

FIG. 6 is a structural diagram of an intermediate substrate 03 of an embodiment of a three-layer composite heat exchange microreactor made of 304 stainless steel.

Use metal isotropic wet chemical etching technology to etch serpentine microchannels 30 for reactants to mix and react on the upper surface of 304 stainless steel intermediate substrate 03. The first section of heat exchange channel 31, the second section of heat exchange channel 32 arranged with the micro reaction channel 30 for providing heat, and the third section of heat exchange channel arranged with the micro reaction channel 30 for removing heat and immediately terminating the reaction 33, the pin mouth 37 that plays centering effect. Wherein, the micro-reaction channel 30 includes inlet through holes 30a, 30b and outlet through holes 30c, the first group of heat exchange channels 31 includes inlet through holes 31a and outlet through holes 31c, and the second group of heat exchange channels 32 includes inlet through holes 32a and The outlet through hole 32c, the third group of heat exchange channels 33 includes an inlet through hole 33a and an outlet through hole 33c. The aforementioned via holes are formed by EDM after the etching process. Align the channel openings and pin openings on the 304 stainless steel intermediate substrate 03 with brass electrodes slightly smaller than the diameter of the channel openings or pin openings on the electric spark drilling machine, and discharge and ablate the holes in sequence. On the electric discharge forming machine tool, a thin sheet-shaped brass electrode is used to discharge and ablate the gap 36 for heat insulation on the 304 stainless steel intermediate substrate 03 .

Fig. 7 is similar to Fig. 6, and shows a structural diagram of an intermediate substrate 03 of a three-layer composite heat exchange microreactor made of 304 stainless steel material from the perspective seen from below.

The electric spark ablation technology is used to form through holes and thermal insulation gaps on the 304 stainless steel sealing plate 05. Use cylindrical brass electrodes on the 304 stainless steel sealing plate 05 to drill the reaction fluid inlet through-holes 50a, 50b and outlet through-holes 50c, the first group of heat exchange fluid inlet through-holes 51a and outlet through-holes on the electric spark drilling machine. Holes 51c, the second group of heat exchange fluid inlet through holes 52a and outlet through holes 52c, the third group of heat exchange fluid inlet through holes 53a and outlet through holes 53c, and the pin through holes 57 for centering. On the 304 stainless steel sealing plate 05, a flaky brass electrode is used to discharge and ablate the heat-insulating gap 56 on the electric discharge forming machine tool.

304 stainless steel base plate 01, 304 stainless steel intermediate base plate 02, 304 stainless steel intermediate base plate 03, and 304 stainless steel sealing plate 05 are packaged by vacuum diffusion welding technology after being centered by pins.

The inlets 50a, 50b, 51a, 52a, and 53a are respectively connected to the fluid chemical substance container, and the fluid chemical substance flows into the corresponding channel from the inlet along the direction perpendicular to the sealing plate 05, and passes through the outlet of the channel and the sealing plate along the direction perpendicular to the sealing plate 05 The corresponding outlet on 05 flows out.

Claims (9)

1. A compound heat exchange microreactor, consisting of a sealing plate (05) and at least one substrate, the upper surface of the substrate has micro reaction channels (10) and heat exchange channels, each channel has at least one inlet and one outlet; the sealing plate (05) is provided with a series of inlet through holes and outlet through holes, and respectively correspond to the inlet and outlet of each channel on the substrate; there is at least one group of corresponding partitions in the substrate and the sealing plate (05) Thermal slots (16), (56), the insulating slots can be formed by removing solid material or filling with insulating material. 2. The reactor according to claim 1, characterized in that there is a micro-scale micro-reaction channel on the substrate, and at least two micro-scale or millimeter-scale heat exchange channels. 3 . The reactor according to claim 1 , characterized in that the heat exchange channels are arranged compactly in sections in a wave or serpentine form along with the micro reaction channels ( 10 ). 4. The reactor according to claim 1, wherein when the number of substrates exceeds one, the inlets and outlets of all channels on the middle substrate are through holes. 5. The reactor according to claim 1, wherein the fluid medium flows into the microreactor along the inlet along the vertical direction of the plate surface, and flows out of the microreactor along the outlet along the vertical direction of the plate surface. 6. The reactor according to claim 1, characterized in that the base plate and the sealing plate (05) are made of silicon, silicon compound, ceramics, metal, heat-resistant glass, silicon and heat-resistant glass, or silicon compound and heat-resistant Hot glass composition. 7. The reactor according to claim 1, characterized in that said base plate and sealing plate (05) are processed by milling, chemical etching, plasma etching, electric spark ablation, laser ablation or LIGA technology. 8. The reactor according to claim 1, characterized in that said substrate and sealing plate (05) are packaged by bonding or diffusion welding. 9. The application of a reactor as claimed in claim 1 in the measurement and analysis of chemical reaction heat absorption or heat release.

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