阅读说明：本技术 一种多孔陶瓷及其制备方法和应用 (Porous ceramic and preparation method and application thereof ) 是由 郭文明 肖汉宁 胡天赐 于 2020-07-03 设计创作，主要内容包括：本发明公开了一种多孔陶瓷,包括碳化硅多孔陶瓷基体；所述碳化硅多孔陶瓷基体的孔壁表面附着有碳化硅薄膜；所述碳化硅薄膜中镶嵌有纳米镍颗粒。本发明还公开了一种包括所述多孔陶瓷的催化微反应器和催化微反应系统,以及所述催化微反应器的制备方法。所述多孔陶瓷可减小反应空间,有助于实现重整制氢系统的小型化,纳米镍颗粒镶嵌于碳化硅薄膜中可提高催化剂负载的结合强度,有助于实现车载在线制氢。(The invention discloses a porous ceramic, which comprises a silicon carbide porous ceramic matrix; a silicon carbide film is attached to the surface of the pore wall of the silicon carbide porous ceramic matrix; and nano nickel particles are embedded in the silicon carbide film. The invention also discloses a catalytic microreactor and a catalytic microreaction system comprising the porous ceramic, and a preparation method of the catalytic microreactor. The porous ceramic can reduce the reaction space, is beneficial to realizing the miniaturization of a reforming hydrogen production system, and the nano nickel particles are embedded in the silicon carbide film, so that the bonding strength of the catalyst load can be improved, and the vehicle-mounted on-line hydrogen production can be realized.)

1. A porous ceramic, characterized by:

comprises a silicon carbide porous ceramic matrix;

the silicon carbide porous ceramic matrix is provided with micron-sized macropores;

a silicon carbide film is attached to the surface of the pore wall of the micron-sized macropore;

and nano nickel particles are embedded in the silicon carbide film.

2. The porous ceramic of claim 1, wherein:

the apparent porosity of the silicon carbide porous ceramic matrix is 30-80%;

the aperture of the micron-sized macropore is 5-200 microns;

the silicon carbide film comprises an amorphous silicon carbide film;

the thickness of the silicon carbide film is 2-20 mu m;

the particle size of the nano nickel particles is 2-200 nm.

3. The porous ceramic of claim 1, wherein:

the silicon carbide porous ceramic matrix is one selected from recrystallized silicon carbide porous ceramic, reaction-bonded silicon carbide porous ceramic, oxide-bonded silicon carbide porous ceramic, pressureless solid-phase sintered silicon carbide porous ceramic or liquid-phase sintered silicon carbide porous ceramic.

4. A catalytic microreactor characterized by: comprising the porous ceramic.

5. The method of making a catalytic microreactor as claimed in claim 4 wherein: the method comprises the following steps:

dipping the silicon carbide porous ceramic matrix in reverse microemulsion, drying, pre-oxidizing, cracking, calcining and processing to obtain the catalytic microreactor;

the reverse microemulsion comprises an oil phase in which a silicon source and a carbon source are dissolved, a water phase in which nickel ions are dissolved and an emulsifier; the silicon source is an organic silicide which can generate reducing gas; the carbon source is an organic matter capable of adjusting the viscosity and the surface tension of the oil phase.

6. The method of making a catalytic microreactor as claimed in claim 5 wherein:

the dipping time is 30-120 min;

the drying temperature is 30-50 ℃;

the drying time is 6-12 h;

the temperature of the pre-oxidation treatment is 240-260 ℃;

the time of the pre-oxidation treatment is 100-150 min;

the atmosphere of the cracking treatment is inert atmosphere;

the inert atmosphere comprises argon or nitrogen;

the temperature rise speed of the cracking treatment is 1-3 ℃/min;

the temperature of the cracking treatment is 450-800 ℃;

the heat preservation time of the cracking treatment is 30-240 min.

7. The method of making a catalytic microreactor as claimed in claim 5 wherein:

the reverse microemulsion is a water-in-oil reverse microemulsion;

the content of an oil phase in the reverse microemulsion is 65-80 wt%, the content of a water phase is 8-31 wt%, and the content of an emulsifier is 4-12 wt%;

the organic solvent of the oil phase is one selected from cyclohexane, xylene or toluene.

In the oil phase, the content of the organic solvent is 60-90 wt%;

in the oil phase, the weight ratio of the carbon source to the silicon source is 1: 0.25-4;

the carbon source is one or more selected from epoxy resin, phenolic resin, coal pitch, ethyl cellulose or polystyrene;

the silicon source comprises polycarbosilane;

the water phase is a nickel salt water solution;

the nickel salt comprises nickel nitrate;

the concentration of the aqueous phase is 3 to 63 wt%.

8. The method for preparing a porous ceramic according to claim 5, wherein:

the emulsifier comprises a main emulsifier and a secondary emulsifier;

in the emulsifier, the content of the main emulsifier is 65-95 wt%;

in the emulsifier, the content of the auxiliary emulsifier is 5-35 wt%;

the primary emulsifier comprises CTAB;

the secondary emulsifier is one or more selected from Span80, DTAC, SDS or AOT.

9. A catalytic microreaction system, comprising: comprises a gas conveying device, the catalytic micro-reactor and a heating device.

10. Use of a catalytic micro-reaction system according to claim 9, characterized in that:

application to the conversion of organic liquid fuels into hydrogen;

the organic liquid fuel comprises C1-C5 alcohol.

Technical Field

The invention relates to porous ceramic and a preparation method and application thereof, belonging to the field of porous ceramic.

Background

In recent years, as fossil energy is gradually exhausted and the urban air quality is adversely affected by the rapid increase in the number of fuel vehicles, the popularization of new energy vehicles has been rapidly spreading.

The new energy automobile comprises a new energy automobile using a hydrogen fuel cell. The new energy automobile using the hydrogen fuel cell can directly convert hydrogen energy into electric energy to drive the automobile to run, and only water is generated without generating CO₂And the like, so that the method has the advantages of high efficiency, environmental protection and the like, and is one of the development directions of new energy automobiles in the future.

However, in the current automobiles using hydrogen as an energy source, the storage mode of hydrogen is mainly to provide hydrogen for the vehicle-mounted fuel cell through a high-pressure gas storage tank. Because hydrogen has the characteristics of flammability and explosiveness, and meanwhile, the high-pressure gas tank can bring potential safety hazards in the driving process of the automobile, and the defects limit the market acceptance of the automobile taking hydrogen as an energy source.

Therefore, the development of a vehicle-mounted hydrogen production device capable of directly and rapidly converting liquid fuel into hydrogen can greatly accelerate the popularization of fuel cell vehicles.

Disclosure of Invention

The first purpose of the invention is to provide a porous ceramic which can efficiently, quickly and stably carry out catalytic reforming on liquid fuel to obtain hydrogen.

The second purpose of the invention is to provide an application of the porous ceramic.

A third object of the present invention is to provide a catalytic microreactor comprising said porous ceramic.

A fourth object of the present invention is to provide an application of said catalytic microreactor.

The present invention provides a porous ceramic having a high porosity,

comprises a silicon carbide porous ceramic matrix;

the silicon carbide porous ceramic matrix is provided with micron-sized macropores;

a silicon carbide film is attached to the surface of the pore wall of the micron-sized macropore;

and nano nickel particles are embedded in the silicon carbide film.

The porosity of the silicon carbide porous ceramic matrix is 30-80%.

The pore diameter of the micron-sized macropore is 5-200 microns.

The silicon carbide film is amorphous silicon carbide film.

The thickness of the silicon carbide film is 2-20 mu m.

The particle size of the nano nickel particles is 2-200 nm.

The porous silicon carbide ceramic matrix is one selected from recrystallized silicon carbide porous ceramic, reaction bonded silicon carbide porous ceramic, oxide bonded silicon carbide porous ceramic, pressureless solid-phase sintered silicon carbide porous ceramic or liquid-phase sintered silicon carbide porous ceramic.

The invention provides a catalytic microreactor comprising the porous ceramic.

The invention also provides a preparation method of the catalytic microreactor, which comprises the following steps:

dipping the silicon carbide porous matrix in the reverse microemulsion, drying, pre-oxidizing, cracking, calcining and processing to obtain the catalytic microreactor;

the reverse microemulsion comprises an oil phase in which a silicon source and a carbon source are dissolved, a water phase in which nickel ions are dissolved and an emulsifier; the silicon source is an organic silicide which can generate reducing gas; the carbon source is an organic matter capable of adjusting the viscosity and the surface tension of the oil phase.

The carbon source is an organic matter capable of adjusting the viscosity and the surface tension of the oil phase.

The dipping time is 30-120 min.

The drying temperature is 30-50 ℃.

The drying time is 6-12 h.

The temperature of the pre-oxidation treatment is 240-260 ℃.

The time of the pre-oxidation treatment is 100-150 min.

The atmosphere of the cracking treatment is inert atmosphere.

The inert atmosphere comprises argon or nitrogen.

The temperature rise rate of the cracking treatment is 1-3 ℃/min.

The temperature of the cracking treatment is 450-800 ℃.

The heat preservation time of the cracking treatment is 30-240 min.

The reverse microemulsion is a water-in-oil reverse microemulsion.

The content of the oil phase in the reverse microemulsion is 65-80 wt%, the content of the water phase is 8-31 wt%, and the content of the emulsifier is 4-12 wt%.

The organic solvent of the oil phase is one selected from cyclohexane, xylene or toluene.

In the oil phase, the content of the organic solvent is 60-90 wt%.

In the oil phase, the weight ratio of the carbon source to the silicon source is 1: 0.25-4.

The carbon source is one or more selected from epoxy resin, phenolic resin, coal pitch, ethyl cellulose or polystyrene.

The silicon source comprises polycarbosilane.

The water phase is an aqueous solution of nickel salt.

The nickel salt includes nickel nitrate.

The concentration of the aqueous phase is 3 to 63 wt%.

The emulsifier comprises a main emulsifier and a secondary emulsifier.

In the emulsifier, the content of the main emulsifier is 65-95 wt%.

In the emulsifier, the content of the auxiliary emulsifier is 5-35 wt%.

The primary emulsifier comprises CTAB.

The secondary emulsifier is one or more selected from Span80, DTAC, SDS or AOT.

The invention provides a catalytic micro-reaction system, which comprises a gas conveying device, a catalytic micro-reactor and a heating device.

The invention also provides an application of the catalytic micro-reaction system, which is applied to converting organic liquid fuel into hydrogen.

The organic liquid fuel comprises C1-C5 alcohol.

Drawings

FIG. 1 is a photomicrograph of the porous ceramic prepared in example 1.

FIG. 2 is a photomicrograph of the porous ceramic prepared in example 3.

FIG. 3 is an X-ray diffraction pattern of nanoparticles of the porous ceramic. Wherein FIG. 3(a) is an X-ray diffraction pattern of nickel nanoparticles of porous ceramics prepared by adding nickel salts of different weights, which respectively corresponds to the X-ray diffraction patterns of the nickel nanoparticles prepared in examples 1 to 3 from the bottom up. FIG. 3(b) X-ray diffraction pattern of nanoparticles of the porous ceramic prepared in comparative example 1. As shown, the nickel salt may be reduced in situ to form elemental Ni in the presence of polycarbosilane. No polycarbosilane can be obtained, but only NiO can be obtained.

FIG. 4 is a TEM photograph of the porous ceramic prepared in example 1. As shown in the figure, the nano Ni catalyst is embedded in the polycarbosilane cracking product SiC_xO_yMedium, quilt SiC_xO_yAnd (4) well dividing.

FIG. 5 is a schematic view of a catalytic micro-reaction system for reforming ethanol steam

FIG. 6 is a schematic structural view of the porous ceramic of the present invention

Detailed Description

The invention provides a porous ceramic, which comprises a silicon carbide porous ceramic matrix; a silicon carbide film is attached to the surface of the pore wall of the micron-sized macropore of the silicon carbide porous ceramic matrix; and nano nickel particles are embedded in the silicon carbide film. The porous ceramic can catalyze the decomposition of alcohol liquid fuel to generate hydrogen in the presence of water vapor. The alcohol liquid fuel includes but is not limited to methanol, ethanol or glycerol, etc.

Taking Ethanol Steam Reforming (ESR) as an example, ethanol and steam are introduced into the catalytic microreactor at a temperature of 500-1000 ℃, and ethanol and steam can react to generate hydrogen and carbon dioxide under the catalysis of the nano nickel particles, and the specific reaction equation is as follows:

in the porous ceramic, the nano nickel particles are embedded in the silicon carbide film in an isolated manner. After the nano nickel particles are wrapped by the silicon carbide, the high-temperature migration potential barrier of the nano nickel particles can be improved, so that the growth of the particle size of the nano nickel particles at high temperature is effectively avoided, the maintenance of the micro morphology of the nano nickel particles is facilitated, the maintenance of higher catalytic activity of the nano nickel particles is facilitated, and the service life of the microreactor is further prolonged. Moreover, the improvement of the high-temperature migration potential barrier of the nano nickel particles also enables the nano nickel particles with catalytic action to recover the activity through heat treatment when being poisoned, and simultaneously avoids the growth of the nano nickel particles and the loss of the catalytic activity. The poisoning of the nano nickel particles in the invention refers to the reduction of the catalytic activity of the nano nickel particles caused by the deposition of carbon on the active sites of the nano nickel particles in the process of preparing hydrogen by catalytic reforming. Meanwhile, the nano nickel particles are inlaid and firmly combined in the silicon carbide film, so that the direct combination of the nano nickel particles and the surface of the inert and smooth porous silicon carbide ceramic matrix is avoided, the load combination strength of the nano nickel particles is improved, the nano nickel particles are effectively prevented from falling off when steam flows are introduced into the catalytic microreactor at high speed and high pressure, and the service life of the catalytic microreactor is prolonged.

In the porous ceramic, the porous ceramic matrix and the ceramic film are both made of silicon carbide. Because the porous ceramic matrix and the ceramic film are made of the same material, the compatibility between the porous ceramic matrix and the ceramic film is excellent, so that the ceramic film can be stably and firmly attached to the surface of the hole wall of the porous ceramic matrix, and the reliability of the catalytic microreactor is improved. Moreover, the porous ceramic matrix and the ceramic film have the same thermal expansion coefficient, so that the porous ceramic matrix and the ceramic film keep the same expansion amount when the catalytic microreactor is heated, the ceramic film is prevented from falling off, and the reliability of the catalytic microreactor is improved. Meanwhile, the porous ceramic can stably maintain the temperature uniformity of each part thereof due to the high thermal conductivity of silicon carbide, thereby maintaining the reaction uniformity. Meanwhile, the high thermal conductivity of the silicon carbide can also enable the catalytic microreactor to rapidly obtain heat from the outside, so that the stability of the reaction is maintained. Moreover, the high-temperature strength of the silicon carbide ceramic is high, so that the silicon carbide porous ceramic matrix can meet the pressure required to be borne by the hydrogen production by steam reforming and the strength required to be borne by the system during assembly. The excellent corrosion resistance of the silicon carbide can ensure that the silicon carbide porous ceramic matrix and the silicon carbide film can meet the requirement of long-term hydrogen production without being corroded by water vapor and the like on the premise of high specific surface area. The silicon carbide has a low thermal expansion coefficient, so that the size change of the silicon carbide porous ceramic matrix and the silicon carbide film is small in the hydrogen production process, and the catalytic microreactor can stably run.

In certain embodiments of the present invention, porous silicon carbide having a porosity of 30 to 80% is used as the matrix of the porous ceramic. Those skilled in the art will appreciate that the solution of the present invention can be realized by using porous silicon carbide, and preferably, the porous ceramic with moderate strength can be obtained by using a porous ceramic of silicon carbide with a porosity of 30-80% as a matrix of the porous ceramic.

In certain embodiments of the present invention, the porous ceramic matrix employed is porous silicon carbide having micron-sized macropores with an average pore size of 5-200 microns. Those skilled in the art will appreciate that the solution of the present invention can be implemented by using porous silicon carbide with micron-sized pore size. When the pore diameter is larger than 200 microns, the specific surface area of the porous ceramic is low, the amount of the loaded nano nickel is small, the hydrogen production efficiency is low, and the hydrogen production by reforming can still be realized. When the pore size is less than 5 μm, the gas passing efficiency is low, the efficiency of hydrogen production is reduced, but reforming hydrogen production can be still achieved.

In some embodiments of the present invention, the silicon carbide film in the porous ceramic is an amorphous silicon carbide film converted from a silicon source. Preferably, the thickness of the silicon carbide film is 2-20 μm.

In certain embodiments of the present invention, the particle size of the nano nickel particles in the porous ceramic is 2 to 200 nm. Those skilled in the art will appreciate that the nano-sized nickel particles can implement the technical solution of the present invention.

In certain embodiments of the invention, the matrix of the porous ceramic is selected from one of recrystallized silicon carbide porous ceramic, reaction bonded silicon carbide porous ceramic, oxide bonded silicon carbide porous ceramic, pressureless solid phase sintered silicon carbide porous ceramic, or liquid phase sintered silicon carbide porous ceramic. As can be understood by those skilled in the art, the physical and chemical properties of the porous silicon carbide ceramic prepared by other methods are not greatly different, and therefore, the technical scheme of the invention can also be realized.

The invention also provides a catalytic microreactor prepared from the porous ceramic. The catalytic microreactor can convert organic liquid fuel into hydrogen mildly, efficiently and stably.

The invention also provides a preparation method of the catalytic microreactor, which comprises the following steps: dipping the porous silicon carbide substrate in the reverse microemulsion, drying, pre-oxidizing, cracking, calcining and processing to obtain the porous silicon carbide ceramic material; the reverse microemulsion comprises an oil phase dissolved with a silicon source capable of generating reducing gas and a carbon source capable of adjusting the viscosity and the surface tension of the oil phase, a nickel ion dissolved water phase and an emulsifier. The carbon source can be adopted to improve the film forming property of the reverse microemulsion by adjusting the viscosity and the surface tension of the oil phase. According to the preparation method of the catalytic microreactor, a silicon source capable of generating reducing atmosphere is used as a precursor of the silicon carbide film embedded with the nano nickel particles. After the silicon source is adopted to carry out cracking reaction, the silicon carbide film generated by cracking can be well combined with the porous silicon carbide substrate. Because the silicon source and the nickel ions exist in the form of microemulsion after being mixed, when the porous silicon carbide matrix is soaked in the microemulsion, the nickel ions can be uniformly adsorbed on the surface of the porous ceramic. This can realize the high-efficient and even load of nanometer nickel granule on the carborundum substrate surface. Meanwhile, the silicon source can generate reducing atmosphere in the cracking reaction process, and the reducing atmosphere can reduce nickel oxide generated by oxidizing nickel ions at high temperature in situ at high temperature to directly obtain nano nickel particles, so that the silicon source can reduce the process of reducing the nickel ions independently, simplify the preparation method of the porous ceramic and save the production cost.

In certain embodiments of the present invention, the time for dipping the silicon carbide substrate in the reverse microemulsion is 30-120 min. The dipping time is too short, nickel ions, silicon sources and carbon sources adsorbed on the surface of the silicon carbide substrate are too little, and the production efficiency is reduced due to too long dipping time.

In certain embodiments of the invention, the temperature of the drying is from 30 to 50 ℃.

In certain embodiments of the invention, the drying time is 6 to 12 hours. .

In some embodiments of the present invention, the pre-oxidation treatment temperature is 240-260 ℃. The non-melting treatment of the polycarbosilane is realized through pre-oxidation.

In some embodiments of the present invention, the time of the pre-oxidation treatment is 100-150 min.

In certain embodiments of the present invention, the atmosphere of the cleavage treatment is an inert atmosphere. Preferred inert atmospheres include nitrogen, argon. The invention can also be practiced with other types of inert gases.

In some embodiments of the present invention, the temperature of the cracking treatment is raised to 450-.

In certain embodiments of the present invention, the inverse microemulsion has an oil phase content of 65 to 80 wt%, an aqueous phase content of 8 to 31 wt%, and an emulsifier content of 4 to 12 wt%;

in some embodiments of the present invention, the carbon source is one or more selected from epoxy resin, phenolic resin, coal pitch, ethyl cellulose, and polystyrene. The carbon source can be used as a carbon source on one hand and can be used as a high-viscosity organic matter on the other hand, and the viscosity and the surface tension of the oil phase can be adjusted, so that the film forming property of the reverse microemulsion is improved, and the film forming is promoted. It will be appreciated by those skilled in the art that other high viscosity carbon sources may be used to practice the embodiments of the present invention.

In certain embodiments of the present invention, the silicon source employed comprises polycarbosilane. It will be appreciated by those skilled in the art that the solution of the present invention can be practiced with other sources of silicon that create a reducing atmosphere.

In certain embodiments of the present invention, the organic solvent is present in the oil phase in an amount of 60 to 90 wt%. In the oil phase, the weight ratio of the carbon source to the silicon source is 1: 0.25-4.

In certain embodiments of the invention, the aqueous phase is an aqueous solution of a nickel salt. Preferably, the nickel salt comprises nickel nitrate. The concentration of the aqueous phase is 3 to 63 wt%.

In certain embodiments of the present invention, preferably, the reverse microemulsion is a water-in-oil reverse microemulsion.

In some embodiments of the present invention, the organic solvent used in the oil phase is one selected from cyclohexane, xylene or toluene. The invention can also be realized by adopting other polar organic solvents.

In certain embodiments of the present invention, the emulsifier comprises a primary emulsifier and a secondary emulsifier; in the emulsifier, the content of the main emulsifier is 65-95 wt%; in the emulsifier, the content of the auxiliary emulsifier is 5-35 wt%; the primary emulsifier comprises CTAB; the secondary emulsifier is one or more selected from Span80, DTAC, SDS or AOT.

The invention also provides a catalytic micro-reaction system which comprises a gas conveying device, the catalytic micro-reactor, a heating device and the like. The gas conveying device is used for introducing gas into the catalytic microreactor, and the heating device is used for heating the catalytic microreactor to a reaction temperature.

The invention also provides application of the catalytic micro-reaction system in converting organic liquid fuel into hydrogen. The organic liquid fuel comprises C1-C5 alcohol.

In some embodiments of the present invention, the catalytic micro-reaction system may have a conversion rate of ethanol of 98%. It will be appreciated by those skilled in the art that the catalytic microreaction system of the present invention can also catalytically reform other C1-C5 alcohols to produce hydrogen.

In summary, compared with the prior art, the invention has the following beneficial effects:

1. the porous structure in the porous ceramic provides a large number of reaction micro-channels for reforming hydrogen production reaction, and the surface of the pore wall of the porous ceramic can be loaded with a large number of nano nickel particles serving as a catalyst, so that a large number of reaction active sites are provided, the hydrogen production capacity and efficiency can be effectively improved, the reaction space is reduced, and the miniaturization of a reforming hydrogen production system is facilitated.

2. The invention inlays and firmly combines the nano nickel particles as the catalyst in the silicon carbide film, but not directly combines with the inert smooth silicon carbide ceramic surface, thereby greatly improving the combination strength of the catalyst load.

3. The nano nickel particles are independently embedded in the silicon carbide film, so that the high-temperature migration barrier of the nano nickel particles is improved, the particles are effectively prevented from growing at high temperature, and the catalytic activity of the nano nickel particles is favorably maintained.

4. The porous ceramic is silicon carbide ceramic. The silicon carbide ceramic has the characteristics of high heat conductivity coefficient, high strength, corrosion resistance, low expansion coefficient and the like, so that the silicon carbide porous ceramic can transfer heat into the microreactor and maintain the stability of reaction; but also can meet the pressure required to be born by the hydrogen production by steam reforming and the strength which must be born by system assembly; meanwhile, the long-term hydrogen production can be realized under the condition of high specific surface area without being corroded by water vapor and the like; and only minor dimensional changes are produced during the hydrogen production process. These characteristics are all beneficial to the stable operation of the microreactor.

5. According to the preparation method of the porous ceramic, a silicon source capable of generating reducing atmosphere is used as a precursor for preparing the silicon carbide film, on one hand, the silicon carbide film formed through cracking can be well combined with the silicon carbide porous ceramic, and meanwhile, the catalyst nano nickel particles can be fully embedded to realize high-efficiency loading, and the reducing atmosphere formed through cracking can directly reduce nickel oxide obtained after nickel ions are oxidized in situ to obtain the nano nickel particles, so that the link of an independent reducing process is reduced.

6. The microreactor prepared from the porous ceramic can control the reforming hydrogen production reaction in a micron-scale space, simultaneously enables the reforming hydrogen production reaction to be carried out mildly and efficiently, and the reaction speed to be improved by 1-3 orders of magnitude compared with the traditional reactor, thereby realizing the remarkable reduction of the volume of a reaction device and being beneficial to realizing vehicle-mounted on-line hydrogen production.

For better understanding of the above technical solutions, the following detailed descriptions will be made with reference to the drawings and specific embodiments of the specification, but the present invention is not limited to these specific embodiments.

The catalytic microreaction system and test system employed in an embodiment of the invention are shown in figure 5.