CN103480273A - Highly-activity sodium-based solid carbon dioxide absorbent - Google Patents

Abstract

The invention provides a high-activity sodium-based solid carbon dioxide absorbent, comprising an active component, a carrier and a catalyst, wherein the active component is sodium carbonate, accounting for 20-40% of the total mass of the solid absorbent; the carrier is Activated alumina accounts for 50-79% of the total mass of the solid absorbent; the catalyst is one or both of _TiO2 and TiO(OH) ₂ , accounting for 1-10% of the total mass of the solid absorbent; the The preparation method of the absorbent is dipping method, precipitation method, dipping precipitation method or dipping spraying method. The solid absorbent of the present invention belongs to the low-temperature absorbent, the _CO2 absorption temperature is 60-80°C, and the _CO2 desorption temperature is 120-300°C. The raw material of the solid absorbent of the present invention is cheap and easy to obtain, the preparation process is cheap and the process is simple, it is not easy to be deactivated after multiple cycles, and can maintain a high _CO2 removal rate, which is a _CO2 emission reduction technology with low investment and energy consumption An optimization scheme of , which has broad application prospects.

Description

A kind of highly active sodium-based solid carbon dioxide absorbent

technical field

The invention relates to a method for removing and concentrating _CO2 in flue gas produced by burning fossil fuels. The solid absorbent used has wide sources of raw materials and is cheap, the preparation method is simple and easy to implement, and the absorption speed is fast and the conversion rate is high. The invention belongs to the technical field of carbon dioxide emission reduction.

Background technique

The greenhouse effect and its impact have increasingly become the focus of worldwide attention. Among them, the massive emission of greenhouse gases, mainly CO ₂ , is the main cause of the greenhouse effect and its continuous aggravation. Atmospheric carbon dioxide levels have increased by 25% since the Industrial Revolution, far exceeding the entire historical record that scientists could possibly survey for the past 160,000 years, and there is no sign of slowing down. The Intergovernmental Panel on Climate Change predicts that by 2100, the global temperature is estimated to rise by about 1.4-5.8°C, which will have a significant impact on the global environment.

According to the survey results of the International Energy Agency, my country's carbon dioxide emissions rank second in the world, accounting for about 13.6% of the global total. At the same time, with the rapid development of my country's economy, energy consumption will continue to increase. As a responsible big country, my country will face greater international pressure. Therefore, it is imminent to actively carry out basic research on carbon dioxide emission reduction and explore a way to reduce carbon dioxide emission that is in line with my country's national conditions. At present, there are endless technologies aimed at reducing _CO2 emissions. Among them, the technology based on post-combustion decarbonization requires only an additional set of _CO2 separation devices, which has low retrofit costs and high technical feasibility.

As a low-temperature _CO2 absorbent, the alkali metal-based absorbent has a carbonation temperature of only 60-80°C and a regeneration temperature of 120-300°C. The energy required for the reaction system can be completely provided by the waste heat of the tail flue gas, and the energy consumption is comparable to The traditional MEA absorption method is reduced by 16%, which has the advantages of not easy to deactivate, high recycling rate, low energy consumption, and light corrosion to equipment. Therefore, alkali metal-based absorbents have broad application prospects.

From 2000 to 2005, with the support of the Department of Energy in the United States, Louisiana State University, Research Triangle Institute and Church&Dwight conducted research on the dry CO ₂ removal technology of alkali metal carbonates (Na ₂ CO ₃ , K ₂ CO ₃ ), Applied for US patents: No. 6387337B1 (2002.5.14.), No. 6280503B1 (2001.8.28.), etc. In recent years, under the funding of the "21st Century Frontier Programs" of the Korean Ministry of Science and Technology, Kyungpook National University, Yeungnam University, Korea Electric Power Research Institute and Korea Institute of Energy Research have also carried out related research. KEPCO has applied for Chinese patent CN200410101564.0 and US patent USP20060148642. Southeast University in China has also carried out related research on this technology, and found that potassium carbonate impregnated on the carrier activated alumina, coal-based activated carbon, wood-based activated carbon or coarse-porous silica gel can form a stable CO ₂ absorbent. Based on the dry removal of CO ₂ technology with potassium-based absorbents, the invention patent CN200810024780.8 was applied, and the device and method for removing CO ₂ in flue gas by using the absorbent were designed, and the invention patent CN200810122644.2 was applied.

At the same time, Southeast University has also conducted a lot of research on sodium-based solid _CO2 absorbents, and found that after sodium carbonate is impregnated and loaded on the activated alumina carrier, the prepared absorbent has a well-developed pore structure, which promotes the absorption of active components and _CO2 . Sufficient contact is beneficial to the occurrence and progress of the carbon dioxide absorption reaction, but the _CO2 absorption capacity is insufficient and the reaction rate is slow. In order to increase the reaction rate, it is necessary to carry out catalytic modification on the sodium-based solid absorbent. Further research found that: TiO ₂ and TiO(OH) ₂ can play a catalytic role in the reaction of sodium-based solid absorbents to absorb CO ₂ , which can effectively increase the reaction rate with CO ₂ and enhance the absorption capacity of CO ₂ . The properties before and after the carbon dioxide absorption or desorption reaction remain stable, and no by-products are generated, so that the recycling of the solid absorbent and the enrichment of _CO2 obtained by desorption are not affected. One or both of TiO ₂ and TiO(OH) ₂ are impregnated and supported on activated alumina together with sodium carbonate as a catalyst to form a CO ₂ solid absorbent with stable properties and well-developed pores, which can realize fast , Efficient absorption of CO ₂ . In addition, the preparation method of the absorbent of the present invention is simple and easy, avoids some side effects caused by adding binders, and has high economic value and practical value.

Contents of the invention

Technical problem: The present invention aims to obtain a highly active sodium-based solid carbon dioxide absorbent with fast _CO2 absorption rate, high absorption rate, cheap and easy to obtain, stable structure, not easy to deactivate, less corrosion to equipment, and simple and cheap preparation process.

Technical scheme: a kind of highly active sodium-based solid carbon dioxide absorber of the present invention comprises active component, carrier and catalyst, wherein said active component is sodium carbonate; Described carrier is activated alumina; Described catalyst is TiO ₂ and One or two mixtures of TiO(OH) ₂ ; wherein, calculated by the total mass of the absorbent:

The mass content of sodium carbonate is 20%-40% of the total mass of the absorbent,

The mass content of activated alumina is 50%-79% of the total mass of the absorbent,

The mass content of the catalyst is 1%-10% of the total mass of the absorbent.

Sodium carbonate as active component is analytically pure carbonate, or obtained by hydrated sodium carbonate, sodium bicarbonate, sodium hydroxide as a precursor.

The activated alumina used as the carrier is γ-type alumina with a specific surface area greater than 100m ² /g and a well-developed pore structure.

The _CO2 absorption temperature of the solid absorbent is 60-80°C, and the _CO2 desorption temperature is 120-300°C.

The high-activity sodium-based solid carbon dioxide absorbent of the present invention uses sodium carbonate as an active component, activated alumina as an absorbent carrier, and one or both of TiO2 _and TiO(OH) ₂ as a catalyst, and adopts a precipitation method, Prepared by dipping method, dipping precipitation method or dipping spray method. Among them: the mass content of the active component is 20%-40% of the total mass of the absorbent, the mass content of the carrier is 50%-79% of the total mass of the absorbent, and the mass content of the catalyst is 1%-10% of the total mass of the absorbent. %. The absorbent is available in granule and powder form.

The sodium carbonate as the active component is an analytically pure carbonate, which can also be obtained by using hydrated sodium carbonate, sodium bicarbonate, sodium hydroxide, etc. as precursors. The carrier is activated alumina, which belongs to γ-type alumina, with a specific surface area greater than 100m ² /g and a well-developed pore structure.

Beneficial effect: compared with the prior art, the present invention has the following advantages:

(1). The _CO2 absorption temperature of the solid absorbent of the present invention is 60°C to 80°C, and the _CO2 desorption temperature is 120°C to 300°C. The required reaction conditions are easy to obtain, and the required heat can be completely provided by the waste heat of the flue gas.

(2). Compared with ordinary alkali metal-based _CO2 absorbents, the catalyst used in the present invention can effectively increase the reaction rate between the absorbent and _CO2 , improve the removal rate of _CO2 in the flue gas, and the catalyst itself absorbs CO2 Or the properties before and after the desorption reaction remain stable, no by-products are generated, and the recycling of the solid absorbent and the enrichment of _CO obtained by desorption are not affected.

(3). The carrier material activated alumina used in the present invention belongs to γ-type alumina with a specific surface area greater than 100m ² /g, well-developed pore structure, and good load capacity and mechanical strength.

(4). The active component sodium carbonate used in the present invention and the carrier material activated alumina are cheap, easy to obtain and highly economical.

(5). The absorbent of the present invention has a simple preparation process, strong operability, simple and controllable loading of active components and catalysts, and is easy for automatic management. Active components and catalysts are evenly distributed on the surface of the carrier.

(6). The absorbent has high decarbonization efficiency, fast absorption rate, high flue gas purification degree, strong regeneration ability, stable performance, low energy consumption, simple equipment and low corrosion. It is an ideal solid for post-combustion _CO2 capture technology Absorbent, has a good application prospect.

Detailed ways

Example 1

Weigh 2 tons of sodium carbonate and dissolve in water, add 7.9 tons of activated alumina carrier and 0.1 tons of titanium dioxide, and mix and stir thoroughly for 8-12 hours. Then put it at a temperature of 70-90°C for drying; finally, roast the dried absorbent at a temperature of 200-250°C for 2-3 hours at a constant temperature; sieve the roasted samples according to engineering needs.

Example 2

Weigh 4 tons of sodium carbonate to make a solution, put 5 tons of activated alumina carrier, mix and stir for 8-12 hours, and then put it at 70-90°C for drying; put the dried absorbent at 200-250°C 2-3 hours at a constant temperature for roasting and molding; weigh 1 ton of titanium dioxide and put it into water, stir it sufficiently to make a solution, and evenly spray it on the formed absorbent, dry the absorbent prepared after spraying and press Engineering needs to be screened.

Example 3

Weigh 0.5 tons of titanium dioxide into water, put 6.5 tons of activated alumina carrier, stir thoroughly for 8-12 hours, and then dry at 70-90°C; put the dried absorbent at 200-250°C , keep the temperature for 2-3 hours for roasting and forming; weigh 3 tons of sodium carbonate and put it into water, and stir it sufficiently to make a solution, then evenly spray it on the formed absorbent, dry the absorbent prepared after spraying and follow the project Screening is required.

Example 4

Weigh 2 tons of sodium carbonate and dissolve in water, add 7.9 tons of activated alumina carrier and 0.1 tons of TiO(OH) ₂ , and mix and stir thoroughly for 8-12 hours. Then put it at a temperature of 70-90°C for drying; finally, roast the dried absorbent at a temperature of 200-250°C for 2-3 hours at a constant temperature; and sieve the roasted samples according to engineering needs.

Example 5

Weigh 4 tons of sodium carbonate to make a solution, put 5 tons of activated alumina carrier, fully mix and stir for 8-12 hours, and then put it at 70-90°C for drying; dry the absorbent at 200-250°C 2-3 hours at a constant temperature for roasting and molding; weigh 1 ton of TiO(OH) ₂ and put it into water, stir it sufficiently to make a solution, and spray it evenly on the formed absorbent, and spray the prepared absorbent Dry and sieve according to engineering needs.

Example 6

Weigh 0.5 tons of TiO(OH) ₂ into water, put 6.5 tons of activated alumina carrier, stir thoroughly for 8-12 hours, and then dry at 70-90°C; put the dried absorbent at 200- At 250°C, keep the temperature constant for 2-3 hours for roasting and molding; weigh 3 tons of sodium carbonate and put it into water, stir it to make a solution, and spray it evenly on the absorbent after spraying. Dry and sieve according to engineering needs.

Claims (4)

1. a high activity sodium base drikold absorbent, it is characterized in that: this absorbent comprises active component, carrier and catalyst, and wherein said active component is sodium carbonate; Described carrier is activated alumina; Described catalyst is TiO ₂and TiO (OH) ₂in one or both mixture; Wherein, by this absorbent gross mass, calculate:

The 20%-40% that the sodium carbonate mass content is the absorbent gross mass,

The 50%-79% that the activated alumina mass content is the absorbent gross mass,

The 1%-10% that catalyst quality content is the absorbent gross mass.

2. a kind of high activity sodium base drikold absorbent according to claim 1,, it is characterized in that: the sodium carbonate as active component is to analyze pure carbonate, or obtains as predecessor by hydrated sodium carbonate, sodium acid carbonate, NaOH.

3. a kind of high activity sodium base drikold absorbent according to claim 1, it is characterized in that: the activated alumina as carrier is γ type aluminium oxide, and specific area is greater than 100m ²/ g, the pore structure prosperity.

4. a kind of high activity sodium base drikold absorbent according to claim 1, is characterized in that: the CO of described solid absorbent ₂the absorption temperature is 60-80 ℃, CO ₂desorption temperature is 120-300 ℃.