CN108434995B

CN108434995B - Film for desorbing CO2 from aqueous solution containing potassium bicarbonate and preparation method thereof

Info

Publication number: CN108434995B
Application number: CN201810225158.7A
Authority: CN
Inventors: 汤志刚; 郭栋; 丁灏; 娄渲明; 爱博; 李红伟; 贺志敏; 邢潇; 宋笑非; 沈怡君; 王翔迪
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2018-03-19
Filing date: 2018-03-19
Publication date: 2020-11-10
Anticipated expiration: 2038-03-19
Also published as: CN108434995A

Abstract

The invention discloses a method for desorbing CO from a water solution containing potassium bicarbonate in the technical field of pervaporation membrane separation₂And a method for producing the same. The film consists of a basal film and an active layer film, wherein the active layer film comprises polydimethylsiloxane, an active cross-linking agent and inorganic nano material particles; the mass ratio of the active cross-linking agent to the polydimethylsiloxane is 0.1-4, and the mass ratio of the inorganic nano material particles to the polydimethylsiloxane is 0.005-0.1; the inorganic nano material particles are nano SiO₂、TiO₂And TiO (OH)₂More than one of them, the grain diameter is 20 nm-100 nm; the thickness of the active layer film is 10-70 μm. The preparation method comprises the following steps: adding nano inorganic material particles, an active cross-linking agent and a catalyst into the polydimethylsiloxane solution, and carrying out cross-linking reaction to obtain a membrane solution; coating the film liquid on a base film, and evaporating the solvent to form a film. The film is suitable for an aqueous solution system and realizes the treatment of CO in a potassium bicarbonate aqueous solution₂The desorption temperature is reduced to 70-90 ℃.

Description

Desorption of CO from aqueous solution containing potassium bicarbonate2And a method for preparing the same

Technical Field

The invention belongs to the technical field of pervaporation membrane separation,in particular to desorption of CO from aqueous solution containing potassium bicarbonate₂And a method for producing the same.

Background

Due to CO₂The global wide attention is paid to greenhouse effect caused by excessive emission, carbon emission reduction is not slow, CCS is a world-recognized effective way for carbon emission reduction, and a chemical absorption method is considered as the most effective CO due to high absorption rate and high efficiency of the chemical absorption method₂One of the trapping methods. Compared with organic absorbents (such as alcamines), the hot potash process adopts an inorganic absorbent potassium carbonate, which has higher absorbent stability and less loss and is widely concerned. However, potassium carbonate absorbs CO₂The formed potassium bicarbonate is usually heated to desorb CO₂The later cycle use, the energy consumption is higher, await improvement urgently. Stripping desorption with inert gas has also been proposed by researchers, but the process has the presence of CO₂The secondary separation of gas and inert gas.

In recent years, some improvements have been made to the desorption process of the hot potash process. Patent CN204999608U has improved the stability of production operation through the flow transformation, and the desorption of rational utilization waste heat. Patent CN101549274 proposes a super-gravity rotating bed device, which is applied to carbon dioxide capture and desorption process, and can greatly reduce investment and operation cost. Patent CN103170218A discloses a method for regenerating and recovering absorbent by releasing carbon dioxide from modified hot potash absorption solution in a supergravity separation unit under normal temperature and low pressure conditions. The literature (Liuna research on regeneration of hot potash solution by electrolytic process [ D ]. Qinghua university, 2010) proposes regeneration of potassium carbonate absorption solution by electrolytic process to reduce energy consumption in desorption process.

The membrane technology has the advantages of wide application range, flexible and simple operation, small occupied area, low operating cost, easy maintenance, convenient amplification and the like, and is widely applied. Patent CN 104607073A proposes that solvent absorption and membrane desorption are combined, so that the desorption temperature can be greatly reduced, and the energy consumption in the desorption process is reduced; the membrane is suitable for use in the separation of CO from a gas containing CO₂In organic solution of (2) to desorb CO₂There is a need to develop a membrane material suitable for use in aqueous systems.

Disclosure of Invention

The invention aims to provide a method for desorbing CO from an aqueous solution containing potassium bicarbonate₂And a method for producing the same. The specific technical scheme is as follows:

desorption of CO from aqueous solution containing potassium bicarbonate₂The film consists of a base film and an active layer film, wherein the active layer film comprises Polydimethylsiloxane (PDMS), an active cross-linking agent and inorganic nano material particles.

The mass ratio of the active cross-linking agent to the polydimethylsiloxane is 0.1-4, and the mass ratio of the inorganic nano material particles to the polydimethylsiloxane is 0.005-0.1.

The base membrane is made of dimethyl sulfoxide (PS), Cellulose Acetate (CA), cellulose, Polyacrylonitrile (PAN), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or polyethylene terephthalate (PET); the aperture of the basal membrane is 20-60 μm, and the thickness of the active layer membrane is 10-70 μm.

The active cross-linking agent is derived from an organic compound with active groups, and is more than one of vinyl trimethoxy, ethyl silicate, triaminomethyl trimethoxy silane, methyl silicate, polydopamine, N-aminoethyl-3-aminopropyl trimethoxy silane and phenyl triethoxy silane.

The inorganic nano material particles are nano SiO₂、TiO₂And TiO (OH)₂More than one of them, the grain diameter is 20 nm-100 nm.

The desorption of CO from aqueous solutions containing potassium bicarbonate₂The method for producing a film of (2), characterized by comprising the steps of:

(1) preparing membrane liquid: fully mixing polydimethylsiloxane and a solvent, then adding nano inorganic material particles and an active cross-linking agent, and carrying out cross-linking reaction to obtain a membrane liquid;

(2) and coating the film liquid on a base film, and evaporating a solvent to form a film.

In the step (1), the solvent is more than one of n-hexane, n-heptane, n-octane, benzene, toluene and xylene, and the mass fraction of the polydimethylsiloxane solution is 20-80%; the temperature of the crosslinking reaction is 15-35 ℃.

And (2) adding a catalyst into the step (1), wherein the catalyst is dibutyltin dilaurate, and the mass of the catalyst is 0.005-0.30 of that of the active cross-linking agent.

In the step (2), the solvent is evaporated at the temperature of 25-85 ℃ for 2-5 h.

Said desorbing CO₂Desorption of CO from aqueous solutions containing potassium bicarbonate₂The application of (2) is characterized in that the concentration of potassium bicarbonate in the aqueous solution is 5-35 wt%, and the desorption temperature is 70-90 ℃.

The invention has the beneficial effects that: the invention prepares an organic polymer membrane material suitable for an aqueous solution system by adding inorganic nano material particles, and realizes the treatment of CO in a potassium bicarbonate aqueous solution₂The desorption temperature is reduced so as to reduce the energy consumption in the desorption process. Compared with the prior common heating desorption and inert gas desorption, the desorption temperature is reduced from the original 120-130 ℃ to 70-90 ℃, and the desorption energy consumption can be reduced by 35-65%.

Drawings

FIG. 1 shows the desorption of CO from an aqueous solution containing potassium hydrogen carbonate₂A flow chart of the preparation of the membrane of (1).

Detailed Description

The following examples facilitate a better understanding of the invention.

Example 1

Desorption of CO from aqueous solutions containing potassium bicarbonate prepared according to the flow diagram shown in figure 1₂Membrane (catalytic desorption membrane).

Taking 11.5g of dimethyl siloxane (PDMS), adding 45g of n-heptane solvent, and adding TiO₂0.35g of nano material (60nm), and uniform strong dispersion; 1.8g of vinyl trimethoxy silane serving as an active crosslinking agent and 0.5g of dibutyltin dilaurate serving as a catalyst are added, and the mixture is stirred for 2.5 hours at the temperature of 20 ℃; the membrane is prepared by a membrane preparation machine, the basement membrane is a polyacrylonitrile microfiltration membrane (the aperture is 20 microns), the thickness of the active layer membrane is controlled to be 35 microns, and the active layer membrane is evaporated to form the membrane at room temperature.

Testing the membrane performance: from 20% (wt) potassium bicarbonate waterDesorption of CO in solution₂The desorption temperature is 70 ℃, and the desorption rate of the potassium bicarbonate is 40.2 percent.

Example 2

Desorption of CO from aqueous solutions containing potassium bicarbonate prepared according to the flow diagram shown in figure 1₂The film of (1).

Taking 11.3g of PDMS, adding 50g of solvent n-hexane, and adding SiO₂0.55g of nano material (50nm), and uniform strong dispersion; adding 1.5g of active cross-linking agent ethyl silicate and 0.8g of phenyl triethoxysilane, adding 0.5g of catalyst dibutyltin dilaurate, and stirring at 25 ℃ for 3.5 h; the membrane is prepared by a membrane preparation machine, the basement membrane is a poly dimethyl sulfoxide micro-filtration membrane (the aperture is 30 microns), the thickness of the active layer membrane is controlled to be 15 microns, and the active layer membrane is evaporated to form the membrane at 30 ℃.

Testing the membrane performance: desorption of CO from aqueous 25% (wt) potassium bicarbonate solution₂The desorption temperature is 75 ℃, and the desorption rate of the potassium bicarbonate is 45.5 percent.

Example 3

Collecting PDMS 12.5g, adding solvent n-hexane 50g, adding TiO (OH)₂0.65g of nano material (60nm), and uniform strong dispersion; adding 1.5g of active component ethyl silicate, 0.6g of N-aminoethyl-3-aminopropyltrimethoxysilane and 1.1g of polydopamine, adding 0.6g of catalyst dibutyltin dilaurate, and stirring at 35 ℃ for 4 hours; the membrane is prepared by a membrane preparation machine, the basement membrane is a poly dimethyl sulfoxide micro-filtration membrane (the aperture is 30 microns), the thickness of the active layer membrane is controlled to be 70 microns, and the membrane is formed by evaporation at 50 ℃.

Testing the membrane performance: desorption of CO from aqueous 25% (wt) potassium bicarbonate solution₂The desorption temperature is 80 ℃, and the desorption rate of the potassium bicarbonate is 50.3 percent.

Example 4

Taking 15.1g of PDMS and 55g of n-hexane serving as a solvent, and adding TiO₂0.45g of nano material (60nm), and uniform strong dispersion; adding active components of ethyl silicate 1.5g and phenyl triethoxysilane 0.5g1.1g of polydopamine, 0.5g of dibutyltin dilaurate serving as a catalyst is added, and the mixture is stirred for 4.5 hours at the temperature of 25 ℃; the membrane is prepared by a membrane preparation machine, the basement membrane is a poly-cellulose microfiltration membrane (the aperture is 40 microns), the thickness of the active layer membrane is controlled to be 35 microns, and the active layer membrane is evaporated to form the membrane at 70 ℃.

Testing the membrane performance: desorption of CO from aqueous 30% (wt) potassium bicarbonate solution₂The desorption temperature is 85 ℃, and the desorption rate of the potassium bicarbonate is 55.1 percent.

Example 5

Taking 13.2g of PDMS, adding 55g of solvent n-hexane, adding TiO (OH)₂0.55g of nano material (60nm), and uniform strong dispersion; adding 1.5g of ethyl silicate serving as an active component, 0.5g of phenyltriethoxysilane and 1.5g of polydopa, adding 0.5g of dibutyltin dilaurate serving as a catalyst, and stirring at 35 ℃ for 4 hours; the membrane is prepared by a membrane preparation machine, the basal membrane is a polyvinylidene fluoride micro-filtration membrane (the aperture is 60 microns), the thickness of the active layer membrane is controlled to be 15 microns, and the active layer membrane is evaporated to form the membrane at 85 ℃.

Testing the membrane performance: desorption of CO from aqueous 30% (wt) potassium bicarbonate solution₂The desorption temperature is 90 ℃, and the desorption rate of the potassium bicarbonate is 55.8 percent.

Claims

1. Desorption of CO from aqueous solution containing potassium bicarbonate₂The film is characterized by consisting of a base film and an active layer film, wherein the active layer film comprises polydimethylsiloxane, an active cross-linking agent and inorganic nano material particles, and the inorganic nano material particles are nano SiO₂；

Said desorption of CO from aqueous solutions containing potassium hydrogen carbonate₂The membrane of (a) is prepared by a process comprising the steps of:

(2) coating the film liquid on a base film, and evaporating a solvent to form a film;

wherein the solvent in the step (1) is more than one of n-hexane, n-heptane, n-octane, benzene, toluene and xylene, and the mass fraction of the polydimethylsiloxane silica is 20-80%; the temperature of the crosslinking reaction is 15-35 ℃, and the time is 2-5 h;

wherein, a catalyst is also added in the step (1), the catalyst is dibutyltin dilaurate, and the mass of the catalyst is 0.005-0.30 of that of the active cross-linking agent;

wherein the temperature for evaporating the solvent in the step (2) is 25-85 ℃.

2. Desorption CO according to claim 1₂The film of (2) is characterized in that the mass ratio of the active crosslinking agent to the polydimethylsiloxane is 0.1 to 4, and the mass ratio of the inorganic nano-material particles to the polydimethylsiloxane is 0.005 to 0.1.

3. Desorption CO according to claim 1₂The membrane is characterized in that the base membrane is made of dimethyl sulfoxide, cellulose acetate, cellulose, polyacrylonitrile, polytetrafluoroethylene, polyvinylidene fluoride or polyethylene glycol terephthalate; the aperture of the basal membrane is 20-60 μm, and the thickness of the active layer membrane is 10-70 μm.

4. Desorption CO according to claim 1₂The film is characterized in that the active cross-linking agent is more than one of vinyl trimethoxy, ethyl silicate, triaminomethyl trimethoxy silane, methyl silicate, polydopamine, N-aminoethyl-3-aminopropyl trimethoxy silane and phenyl triethoxy silane.

5. Desorption CO according to claim 1₂The film of (2), wherein the particle diameter of the inorganic nano-material particles is 20nm to 100 nm.

6. Desorbing CO as claimed in claim 1₂Desorption of CO from aqueous solutions containing potassium bicarbonate₂Characterized in that the concentration of potassium bicarbonate in said aqueous solution is5 wt% -35 wt%, and the desorption temperature is 70-90 ℃.