A kind of preparation method of modification carbon dioxide calcium-base absorbing agent
Technical field
The present invention relates to a kind of preparation method of modification carbon dioxide calcium-base absorbing agent, be used for removing flue gas CO
2Technology.Belong to environmental pollution prevention and control and clean coal combustion technology field.
Background technology
Climate change is one of global problem of current international community common concern, and has become the key factor that influences various countries' future economy and social sustainable development.In December, 2009, in the climate change conference of Copenhagen, most countries is all recognized the seriousness of the caused environmental problem of climate change, indicates on reply climate change problem, to bear responsibility separately.Reaching of " Copenhagen agreement " is that international community is devoted to whole world reduction of discharging CO
2New milestone.
Carbon dioxide is the main greenhouse gases that cause climate change, global warming.Chinese Government promises to undertake that the CO2 emissions that arrive the year two thousand twenty China unit GDP will reduce 40%-45% than 2005.The completion of this target is to CO
2The reduction that reaches cost of constantly improving of emission-reduction technology has proposed more urgent and difficult task.
At present, catch or remove CO
2Technology, method numerous, like membrane separation technique, amine absorption process, O
2/ CO
2CFBC, burning chemistry chains, rare-earth oxide absorption process, solid absorbent method etc.Can the economic and practical of every kind of technical method will be to determine it obtain the prerequisite of wide range of industrial applications.Utilize the circulation calcination/carbonation Reaction Separation CO of the cheap calcium-base absorbing agents such as lime stone that enrich
2Technical method caused countries in the world scholar's extensive concern.The technological process of this method is as shown in Figure 2, and lime stone is O in calcining furnace
2/ CO
2Calcining (> under the atmosphere; 900 ℃), discharge flue gas and contain high concentration CO
2(>95%) can reclaim.The CaO that generates gets into the carbonating stove and under normal pressure (650-750 ℃) or pressurization (650-850 ℃) condition, carries out the CO in the carbonation reaction absorption flue gas
2CO in the flue gas that the carbonating fire grate goes out
2Content low (<5%) CaCO of reaction generation,
3The regeneration of entering calcining furnace; So circulation realizes CO
2Effectively catch.Yet research shows natural calcium base CO such as lime stone
2There is a serious problem in absorbent: along with the increase of circulation calcination/carbonation reaction times, agglomeration makes the carbonating conversion ratio of absorbent descend rapidly.Normal pressure cyclic carbon acidification reaction 10 times, the carbonating conversion ratio is reduced to below 30%.In order to keep higher CO
2Removal efficiency, needs increase the input amount of fresh absorbent, and the wearing and tearing that this will increase cost, aggravation stove internal heating surface threaten device security, influence economical operation.Therefore, improve calcium base CO
2The long period cyclic carbon souring ability of absorbent and anti-caking power are to CO
2The long-term stability operation of absorption plant has important industrial application value.
Summary of the invention
Technical problem: the technical issues that need to address of the present invention provide a kind of coal-fired flue-gas CO that is used for removing
2The preparation method of high-efficiency composite calcium base absorbant, solve calcium-base absorbing agent and remove CO
2The problem that absorbent easy-sintering, cyclic carbon souring ability are decayed rapidly in the technology.
Technical scheme: conception of the present invention: limestone resource is abundant, cheap and easy to get, and its calcined product has circulation and catches CO
2Advantage; But its calcined product CaO intensity difference, frangible, anti-caking power is poor, cause service life short and pulverize after powder be prone to cause the equipment fouling of heating surface serious, influence problems such as system stability safe operation.The CO that passes through Prepared by Sol Gel Method that the inventor proposes
2Absorbent not only has good anti-sintering and antiwear property, has good pore structure simultaneously and distributes, and is very beneficial for circulation and absorbs CO in the flue gas
2, significantly improved the CO of common calcium-base absorbing agent
2Remove performance.
The present invention is the preparation method who is used for removing the composite calcium-base absorbent of coal-fired flue-gas carbon dioxide, and this method is that calcium nitrate and modifier are dissolved in the salpeter solution; 50-60 ℃ is stirred adding tartaric acid down and forms mixed solution; Above mixed solution is put into 80-85 ℃ of water-bath, dehydration by evaporation 6-8 hour formation gel sample; Put into oven for drying foaming 2-3 hour, porphyrize gets pale yellow powder; Grind the back and calcined 2-3 hour down, make modification carbon dioxide calcium-base absorbing agent at 500-600 ℃.
Described modifier is the nitrate of magnesium, manganese or aluminium; When modifier was magnesium nitrate, calcium was n with the ratio of the amount of substance of magnesium
Ca: n
Mg=10:0.75-10:1.5; When modifier was manganese nitrate, calcium was n with the ratio of the amount of substance of manganese
Ca: n
Mn=100:1-100:2.5: when modifier was aluminum nitrate, calcium was n with the ratio of the amount of substance of aluminium
Ca: n
Al=10:1-10:5.
The ratio of the amount of substance of the metal nitrate in tartaric acid and calcium nitrate and the modifier is n
Tartaric acid: n
Metal leaves Son=1.3:1-1.6:1.
The molar concentration of salpeter solution is 2M.The temperature of gel oven dry is 120-150 ℃.Calcining heat is 500-600 ℃.
Beneficial effect: the method for preparing carbon dioxide composite calcium-base absorbent provided by the present invention, its advantage is: the CO that adopts sol-gal process to obtain
2Absorbent, contained CaO and other metal oxides in the particle, it is more even to distribute, the distribution of pores excellent, anti-agglutinatting property can improve; Consequently not only significantly strengthen the carbonating ability of absorbent, and strengthened the mechanical strength and the wear resistance of absorbent, reduced the loss of absorbent in carbonation, thereby improved the cyclic utilization rate of absorbent.
The present invention has overcome natural calcium base CO such as lime stone
2Absorbent is caught CO in circulation
2In the process conversion ratio decay rapidly, problem such as anti-caking power difference and easy efflorescence, have that preparation technology is simple, easy to operate, the synthetic material formability is good, anti-sintering and antiwear property are strong, advantages such as good cycle.
Description of drawings
Fig. 1 is that modification carbon dioxide calcium-base absorbing agent of the present invention prepares process flow diagram flow chart.
Fig. 2 is calcium-base absorbing agent CO
2Catch process chart.
The specific embodiment
Case study on implementation 1
Take by weighing the Ca (NO of 23.615g
3)
24H
2Mg (the NO of O and 2.5641g
3)
26H
2O (n
Ca: n
Mg=10:1), be dissolved in the salpeter solution that 50ml concentration is 2M; Under 50-60 ℃, in magnetic stirring apparatus, stir the back and add 21.45g tartaric acid (n
Tartaric acid: n
Metal ion=1.3:1), add water to 100ml then, stirred 5-10 minute; Solution after stirring is put into 80-85 ℃ of water-bath, dehydration by evaporation 6-8 hour formation gel sample; And then putting it in 140 ℃ of baking ovens oven dry foaming 3 hours, porphyrize gets pale yellow powder; Move into again in the Muffle furnace in 550 ℃ of calcinings 3 hours, promptly make magnesium-modified carbon dioxide calcium-base absorbing agent.
Case study on implementation 2
Take by weighing the Ca (NO of 23.615g
3)
24H
250%Mn (the NO of O and 0.5495ml
3)
24H
2O solution (n
Ca: n
Mn=100:2), be dissolved in the salpeter solution that 50ml concentration is 2M; Under 50-60 ℃, in magnetic stirring apparatus, stir the back and add 22.95g tartaric acid (n
Tartaric acid: n
Metal ion=1.5:1), add water to 100ml then, stirred 5-10 minute; Solution after stirring is put into 80-85 ℃ of water-bath, dehydration by evaporation 6-8 hour formation gel sample; And then putting it in 130 ℃ of baking ovens oven dry foaming 3 hours, porphyrize gets pale yellow powder; Move into again in the Muffle furnace in 500 ℃ of calcinings 3 hours, promptly make manganese modification carbon dioxide calcium-base absorbing agent.
Case study on implementation 3
Take by weighing the Ca (NO of 23.615g
3)
24H
2Al (the NO of O and 9.37825g
3)
39H
2O (n
Ca: n
Al=10:2.5), be dissolved in the salpeter solution that 50ml concentration is 2M; Under 50-60 ℃, in magnetic stirring apparatus, stir the back and add 22.5g tartaric acid (n
Tartaric acid: n
Metal ion=1.2:1), add water to 100ml then, stirred 5-10 minute; Solution after stirring is put into 80-85 ℃ of water-bath, dehydration by evaporation 6-8 hour formation gel sample; And then putting it in 150 ℃ of baking ovens oven dry foaming 3 hours, porphyrize gets pale yellow powder; Move into again in the Muffle furnace in 600 ℃ of calcinings 3 hours, promptly make aluminium modification carbon dioxide calcium-base absorbing agent.