CN106237834A - A device and method for immobilized enzyme carbonation to fix CO2 - Google Patents

Abstract

The invention discloses a device and method for immobilized enzyme carbonation to fix CO ₂ , based on the hierarchical arrangement of quartz wool-wrapped NdFeB magnetic balls to realize the filling of immobilized carbonic anhydrase to fix CO ₂ . After desulfurization containing CO ₂ , the flue gas enters the packed tower filled with immobilized carbonic anhydrase. Under the catalysis of the immobilized enzyme, CO ₂ is rapidly catalyzed to generate HCO ₃ ^‑ and CO ₃ ^2‑ , and the absorption liquid flows from the top of the packed tower Entering, contacting with gas countercurrent, HCO ₃ ^‑ and CO ₃ ^2‑ enter the ultrasonic leaching tank with the absorption liquid, and react with calcium ions to form calcium carbonate. The present invention uses surface carboxylated Fe ₃ O ₄ as the carrier material used in the immobilization process of carbonic anhydrase, so that the immobilized enzyme has the same magnetic properties as the carrier material, and can effectively solve the problem that the immobilized enzyme packing is easy to lose during tower operation. , not only realize the carbonation and fixation of CO ₂ under low concentration and normal pressure, but also realize the continuous operation of the whole set of equipment.

Description

A device and method for immobilized enzyme carbonation to fix CO2

1. Technical field

_The present invention relates to a device and method for carbonating and fixing _CO2 by immobilized carbonic anhydrase. The method is suitable for capturing CO ₂ in desulfurized net flue gas of a coal-fired power station, and belongs to the field of coal-fired air pollutant control.

2. Background technology

According to statistics, the total global carbon emissions in 2015 were 23.2 billion tons. Huge carbon emissions have seriously affected the human living environment and climate change. The CO ₂ emitted by the combustion of coal-fired power plants is the main source of greenhouse gases, and it is also the main field for controlling and mitigating carbon emissions. The current control methods for CO ₂ include: chemical reagent absorption method (such as ammonia and MEA, etc.), algae carbon fixation method, membrane absorption and separation technology, oxygen-enriched combustion technology (which can obtain high concentration of CO ₂ ), fluidization Bed base dry capture technology, etc. The chemical reagent absorption method and fluidized bed base dry capture technology have been relatively mature in domestic research, but there are problems such as high one-time investment and expensive operation cost.

With the rapid development of biotechnology, the use of carbonic anhydrase biomimetic technology to achieve _CO2 capture and storage has gradually become a hot issue in human research. Carbonic anhydrase is currently found to be the most effective biocatalyst for promoting CO ₂ hydration reaction, and its hydration product HCO ₃ ^- is easy to form thermodynamically stable metal carbonates with metal ions. This biomimetic technology is considered to have important application prospects. Environmentally friendly and feasible carbon sequestration technology. However, due to the shortcomings of free carbonic anhydrase such as poor stability, difficult recovery, variability and inactivation, the industrial application of the enzyme is greatly restricted. In order to solve the above problems, it is necessary to immobilize the enzyme. There are many types of carbonic anhydrase immobilization carriers, mainly acrylamide polymers, chitosan, seaweed salt, mesoporous silica and natural polymers. At present, the recovery methods of immobilized enzymes are mostly filtration and centrifugation, but these two separation methods are relatively cumbersome. Therefore, insoluble magnetic carriers have gradually attracted the attention of researchers, and their immobilized products can be directly separated by a simple and effective external magnetic field, which is a class of carrier materials widely used in industry. When using immobilized enzyme packing to remove CO ₂ , since the particles of the packing itself are relatively small, it is easy to fall off under the air flow and liquid washing, so the surface carboxylated Fe ₃ O ₄ is used as the carrier material; in the gas-liquid two-phase flow, The CO ₂ residence time is short, which makes the CO ₂ removal efficiency low. Therefore, when designing the packed tower, a three-stage packing layer is used, and a gas uniform distribution plate is added at the gas inlet to maximize the gap between the gas and the packing layer. Full contact.

3. Contents of the invention

Purpose of the invention: The purpose of the present invention is to solve the problems that the immobilized enzyme particles in the filler are easy to fall off and the CO ₂ residence time is relatively short, and provide a method based on the hierarchical arrangement of quartz wool-wrapped NdFeB magnetic balls to realize the carbonation and fixation of CO ₂ by immobilized enzymes. The device and method of the present invention have a simple and compact structure, and can effectively solve the problems of easy shedding of carbonic anhydrase and short residence time of _CO2 .

Technical solution: A method for immobilized enzyme carbonation to fix _CO2 . The flue gas containing _CO2 after desulfurization enters the packed tower reactor from the inlet pipe at the bottom of the packed tower, and _CO2 is rapidly catalyzed under the action of immobilized carbonic anhydrase into HCO ₃ ^- and CO ₃ ^2- , the absorption liquid enters the packed tower from the liquid inlet pipe at the top of the tower, and contacts with the gas countercurrently, HCO ₃ ^- and CO ₃ ^2- enter the ultrasonic leaching tank with the absorption liquid, and are separated from the leaching Ca ²⁺ reacts to generate CaCO ₃ and Ca(HCO ₃ ) ₂ .

The immobilized carbonic anhydrase is immobilized by surface carboxylated Fe ₃ O ₄ through chemical and glutaraldehyde cross-linking methods, and the particle diameter is 15-30nm.

A device used in the method for immobilized enzyme carbonation to fix _CO2 , comprising a desulfurization device, a packed tower absorption device, an ultrasonic leaching tank and an absorption liquid pool; the absorption liquid pipe and the absorption liquid at the top of the packed tower absorption device The liquid pool is connected, the inlet pipe at the bottom of the absorption device of the packed tower is connected with the desulfurization device through a static mixer, and the waste liquid pipe at the bottom of the absorption device of the packed tower is connected with the ultrasonic leaching tank; multi-stage packing layers are set in the absorption device of the packed tower , the packing layer The packing layer is, from top to bottom, the surface layer of quartz wool, the immobilized enzyme layer prepared by surface carboxylated Fe ₃ O ₄ as a carrier, the interlayer of quartz wool, and NdFeB magnetic balls.

Upper and lower filter screens are arranged on the upper and lower parts of the packing layer.

An air distribution plate is arranged under the packing layer.

The top of the packed tower absorption device is provided with a mist eliminator.

The top of the packed tower absorption device is provided with an absorption liquid nozzle.

The top of the packed tower absorption device is also provided with an exhaust pipe.

A peristaltic pump is arranged between the absorption liquid pipe and the absorption liquid pool.

Beneficial effect:

(1) The present invention is a device for immobilized enzyme carbonation to fix CO ₂ , that is, a device based on a three-stage hierarchical arrangement of quartz wool-wrapped NdFeB magnetic balls to realize carbonation and fixation of immobilized enzymes for CO ₂ . The capture of CO ₂ after combustion has a simple structure. The gas flows from bottom to top, and the absorption liquid is sprayed from top to bottom, which saves space to the greatest extent.

(2) The airflow uniform distribution plate is used to evenly distribute the airflow, so that _CO2 and carbonic anhydrase packing can be fully contacted. At the same time, the three-stage packing layer can increase the residence time of _CO2 and carbonic anhydrase, and improve the removal efficiency of _CO2 .

(3) The surface carboxylated Fe ₃ O ₄ is used as the carrier material, and the packing layer is laid out by wrapping NdFeB magnetic balls with quartz wool, which greatly reduces the loss of immobilized carbonic anhydrase.

(4) The present invention successfully combines the high-efficiency catalysis of carbonic anhydrase on the _CO2 hydration reaction and the ultrasonically enhanced carbonation reaction, and designs a device for immobilized enzyme carbonation to fix _CO2 , that is, a device based on quartz wool wrapping NdFeB magnetic balls are arranged in stages to realize the carbonation and fixation of _CO2 by immobilized enzymes, which can realize the removal of _CO2 under normal pressure and low concentration conditions, and can also significantly reduce the cost and scale of _CO2 operation. Compared with the prior art, the present invention realizes the in-situ sequestration of CO ₂ and greatly reduces the transportation cost of CO ₂ in the transportation process (the transportation cost accounts for about 30% of the CO ₂ processing cost), while the traditional CO ₂ mine The chemical process is based on the separation of high-concentration CO ₂ , and then converts CO ₂ into CaCO ₃ under high temperature and pressure, which has the disadvantages of slow reaction rate and low conversion rate. The invention can realize the conversion of CO ₂ into CaCO ₃ under the conditions of actual industrial waste gas concentration and normal pressure.

4. Description of drawings

Fig. 1 is a structural representation of the present invention

In the figure: 1-desulfurization device; 2-static mixer; 3-intake pipe; 4-air flow distribution plate; 5-boss; 6-sealing gasket; 7-NdFeB magnetic ball; 8-quartz wool; 9 -immobilized enzyme filler; 10-absorption liquid nozzle; 11-mist eliminator; 12-exhaust pipe; 13-absorption liquid pipe; 14-peristaltic pump; 15-absorption liquid pool; 16-chimney; 17-waste liquid pipe ;18-ultrasonic leaching tank

5. Specific implementation

The following describes a device for carbonating and fixing CO2 with immobilized enzymes according to the present invention, that is, a device for carbonating and fixing _CO2 with immobilized enzymes based _on the hierarchical arrangement of NdFeB magnetic balls wrapped in quartz wool and The method is explained in detail:

A device based on the graded arrangement of quartz wool-wrapped NdFeB magnetic balls to realize the carbonation and fixation of _CO2 by immobilized enzymes. The device includes a gas distribution system, a packed tower absorption device, an ultrasonic leaching tank, an absorption liquid pool, etc.

The absorption device of the packed tower includes a bottom-up air intake pipe, an air flow uniform distribution plate, a carbonic anhydrase packing layer wrapped with NdFeB magnetic balls in three-stage quartz wool, an absorption liquid nozzle, and an absorption liquid inlet pipe. The carbonic anhydrase filler layer of the _three -stage quartz wool wrapped NdFeB magnetic ball is sequentially from top to bottom the surface layer of quartz wool, the immobilized enzyme layer prepared by surface carboxylated _Fe3O4 as a carrier, the interlayer of quartz wool, NdFeB magnetic balls.

The surface carboxylated Fe ₃ O ₄ is a nano-carrier material.

The carbonic anhydrase is commercially available and extracted from bovine hemoglobin.

The fiber diameter of the quartz wool is relatively small, reaching 5-9 microns.

Bosses are provided at the joints of the filling pipes of each stage.

The upper and lower parts of the packing layer are provided with upper and lower filter screens.

The absorption liquid waste containing CO ₃ ^2- and HCO ₃ ^- reacts with Ca ²⁺ in the ultrasonic leaching tank to generate CaCO ₃ and Ca(HCO ₃ ) ₂ .

After the gas flow passes through the packed layer, the remaining gas is discharged through the gas outlet of the packed tower.

The immobilized enzyme is arranged in the quartz wool interlayer, and the NdFeB magnetic balls are placed and distributed under the quartz wool interlayer containing the immobilized enzyme.

A method for immobilized enzyme carbonation and fixation of CO ₂ , that is, a method for the carbonation and fixation of immobilized enzymes to realize the carbonation and fixation of _{CO 2} by quartz wool wrapped NdFeB magnetic spheres, comprising the following steps: The gas distribution system enters the packed tower reactor from the inlet pipe at the bottom of the packed tower, and reaches the packing layer through the air distribution plate. CO ₂ is quickly catalyzed into HCO ₃ ^- and CO ₃ ^2- under the action of immobilized carbonic anhydrase, absorbing The liquid enters the packed tower from the liquid inlet pipe at the top of the tower, and contacts with the gas countercurrently. HCO ₃ ^- and CO ₃ ^2- enter the ultrasonic leaching tank along with the absorption liquid. The remaining gas is discharged from the chimney through the outlet of the packed tower.

Example

As shown in the figure, the present invention is a device for immobilized enzyme carbonation and fixation of _{CO 2} , that is, a device for carbonation and fixation of immobilized enzymes based on the hierarchical arrangement of NdFeB magnetic balls wrapped in quartz wool, including desulfurization device, packed tower absorption device, ultrasonic leaching tank, absorption liquid pool. The packed tower absorption device is made of transparent organic glass. After desulfurization containing _{CO 2} ^, the flue gas ^enters the absorption device _of the packed tower through the desulfurization device 1 from the inlet pipe ₃ at the bottom of the packed tower. The liquid enters the packed tower from the absorption liquid pipe 13 at the top of the tower, and contacts with the gas countercurrently. HCO ₃ ^- and CO ₃ ^2- enter the ultrasonic leaching tank 18 along with the absorption liquid. The remaining gas passes through the mist eliminator 11 and is discharged from the chimney 16 through the exhaust pipe 12 .

The absorption device of the packed tower is provided with an airflow uniform distribution plate 4 to make the airflow evenly distributed and ensure that _CO2 is fully contacted with the immobilized carbonic anhydrase filler.

The packing layer is composed of NdFeB magnetic balls wrapped in quartz wool. The immobilized enzyme is evenly distributed in the interlayer of quartz wool, and a layer of NdFeB magnetic balls is arranged below it. The upper and lower parts of the packing layer are all filter screens. Effectively prevent the filler layer from being deformed and immobilized carbonic anhydrase falling off due to gas-liquid scouring.

The packing layer has three stages, and each section of packing pipe is detachable, and a boss is provided at the junction.

The immobilized enzyme is immobilized by surface carboxylated Fe ₃ O ₄ through chemical and glutaraldehyde cross-linking methods, and the prepared immobilized enzyme has certain mechanical strength, good thermal stability, operational stability and storage stability , The particle size of the product can reach the nanometer level: 15-30nm. Since Fe ₃ O ₄ itself is a magnetic substance, the obtained immobilized enzyme is also a magnetic substance.

In the ultrasonic leaching tank, waste liquid containing HCO ₃ ^- and CO ₃ ^2- absorbing liquid enters the ultrasonic leaching tank, and reacts with Ca ²⁺ leached in the leaching tank to generate CaCO ₃ and Ca(HCO ₃ ) ₂ .

In the example of the present invention, the diameter of the packed tower is 50 mm, and the thickness of each packing layer is 30 mm. The packing layer is provided with a porous support plate, and 50 small holes are evenly distributed, and the small hole diameter is 3 mm. The diameter of the NdFeB magnetic balls at the filler layer is 5 mm, and they are evenly distributed on the quartz wool.

As shown in Figure 1, the upper and lower sides of the packed tower are respectively provided with inlet pipes, gas outlet pipes, absorption liquid inlet pipes and absorption liquid waste liquid pipes. The diameter of the gas inlet and outlet pipes is 6mm, and the diameter of the liquid inlet and outlet pipes is 10mm.

The packed tower reactor is made of plexiglass, and the height of the whole tower is 1200mm. In order to ensure that the packed tower can withstand a certain pressure, the thickness of the plexiglass is 3mm. Seal with a sealing ring.

Using an immobilized enzyme carbonation and fixation of CO ₂ of the present invention, that is, a test device for capturing coal-burning flue gas based on a device for carbonation and fixation of CO ₂ by immobilized enzyme carbonation based on quartz wool-wrapped NdFeB magnetic spheres. Since the concentration after the desulfurization device in the coal-fired flue gas is about 13%-18%, so in the _CO2 absorption experiment, when the parameters are: the amount of immobilized enzyme 1.2g (that is, 4mg free carbonic anhydrase), gas volume 0.5L /min, the CO ₂ concentration is 16.8%, and the liquid-gas ratio is 28L/m ³ . At this time, the CO ₂ outlet concentration is 7.9%, that is, the CO ₂ removal efficiency reaches 52.97%. While in the blank experiment, the _CO2 concentration hardly decreased, still: 16.45%.

Finally, it should be noted that the present invention is not limited to the examples. Those skilled in the art can make appropriate modifications to the present invention, and these modifications are all included in the scope defined by the claims of the present application.

Claims (9)

1. an immobilized enzyme carbonating fixes CO₂Method, it is characterised in that containing CO₂Flue gas after desulfurization is bottom packed tower Air inlet pipe enters in packed tower reactor, CO₂Under the effect of immobilization carbonic anhydrase, quick catalysis becomes HCO₃ ^-And CO₃ ^2-, absorb Liquid enters packed tower from the feed tube of top of tower, contacts with back flow of gas, HCO₃ ^-And CO₃ ^2-Ultrasound wave leaching is entered into absorbing liquid Take in groove, and leach the Ca²⁺Reaction generates CaCO₃With Ca (HCO₃)₂。

Immobilized enzyme carbonating the most according to claim 1 fixes CO₂Method, it is characterised in that described immobilization carbon Anhydride enzyme is by the Fe of surface carboxyl groups₃O₄Being fixed by chemistry and Euplotes woodruffi, particle diameter is at 15-30nm.

3. fix CO for the immobilized enzyme carbonating described in claim 1 or 2 for one kind₂Method in device, its feature exists In: include desulfurizer (1), packed tower absorption plant, ultrasound wave leaching groove (18) and absorb liquid pool (15)；Packed tower absorbs dress The absorbing liquid pipe (13) in top set portion is connected with absorbing liquid pool, and the air inlet pipe (3) bottom packed tower absorption plant passes through static mixing Device (2) is connected with desulfurizer (1), and the sewer pipe (17) bottom packed tower absorption plant is connected with ultrasound wave leaching groove (18)； Arranging multistage packing layer in described packed tower absorption plant, described packing layer is followed successively by silica wool top layer, table from top to bottom The Fe that face is carboxylated₃O₄The immobilized enzyme layer prepared as carrier, silica wool interlayer, neodymium-iron-boron ball.

The most according to claim 3 fix CO for immobilized enzyme carbonating₂Method in device, it is characterised in that The upper and lower of packing layer is equipped with upper and lower filter.

The most according to claim 3 fix CO for immobilized enzyme carbonating₂Method in device, it is characterised in that fill out The lower section of the bed of material is provided with airflow uniform distribution plate (4).

The most according to claim 3 fix CO for immobilized enzyme carbonating₂Method in device, it is characterised in that institute The packed tower absorption plant top stated is provided with mesh mist eliminator (11).

The most according to claim 3 fix CO for immobilized enzyme carbonating₂Method in device, it is characterised in that institute The packed tower absorption plant top stated is provided with absorbing liquid nozzle (10).

The most according to claim 3 fix CO for immobilized enzyme carbonating₂Method in device, it is characterised in that institute The packed tower absorption plant top stated is additionally provided with exhaustor (12).

The most according to claim 3 fix CO for immobilized enzyme carbonating₂Method in device, it is characterised in that institute It is provided with peristaltic pump (14) between absorbing liquid pipe and the absorption liquid pool stated.