A CO2 sequestration system and process applicable to the Gobi desert and saline-alkali land environments

Abstract

The present invention discloses a CO2 sequestration system and process applicable to the Gobi desert and saline-alkali land environments. The system includes a pressurized water input section and a CO2 input section. The pressurized water input section includes a spray vertical well, a water pump, and a spray pipeline. A plurality of vertically arranged spray vertical wells are evenly spaced and drilled. The input end of the water pump is connected to a water tank, and the output end is connected to the spray pipeline. The spray pipeline includes spray risers communicated and arranged in each spray vertical well, and nozzles are provided on the spray risers. The CO2 input section includes a CO2 input pipeline connected to a CO2 capture source through a control valve. The CO2 input pipeline includes a plurality of CO2 input risers arranged underground and extending vertically upward. The CO2 input risers are in a slotted pipe structure, and the CO2 input risers are evenly spaced and arranged around the spray vertical wells. The present invention can achieve the sequestration of CO2 in the form of salts underground, and can provide a new solution to the carbon sink problem in modern carbon cycle research.

Description

Technical Field

[0001] The present invention relates to a CO2 sequestration system and process, specifically a CO2 sequestration system and process applicable to the Gobi desert and saline-alkali land environments, belonging to the technical field of CO2 sequestration. Background Art

[0002] Global warming has become the main environmental problem faced by humanity at present and is also the focus of attention of the public and the scientific community. The main reason for the global greenhouse effect is the increase in the concentration of CO2 in the atmosphere. Since the global industrialization process, in addition to the continuous increase in the use of fossil fuels, the change in soil use patterns, which damages the global carbon cycle balance, is also one of the main reasons for the reduction of the soil carbon pool and the increase in the atmospheric CO2 concentration. Summary of the Invention

[0003] Aiming at the problems existing in the above-mentioned prior art, the present invention provides a CO2 sequestration system and process applicable to the Gobi desert and saline-alkali land environments, which can achieve the sequestration of CO2 in the form of salt underground and can provide a new solution to the carbon sink problem in modern carbon cycle research.

[0004] To achieve the above object, the CO2 sequestration system applicable to the Gobi desert and saline-alkali land environments includes a pressurized water input part and a CO2 input part;

[0005] The pressurized water input part includes a spray vertical well, a water pump, and a spray pipeline; the vertically arranged spray vertical well is drilled from the ground underground, and multiple spray vertical wells are drilled at equal intervals; the input end of the water pump arranged on the ground is connected to a water tank, and the output end is connected to the spray pipeline; the spray pipeline includes spray risers communicated in each spray vertical well, and spray nozzles are provided on the spray risers.

[0006] The CO2 input part includes a CO2 input pipeline connected to a CO2 capture source through a control valve. The CO2 input pipeline includes multiple CO2 input risers arranged underground and extending vertically upward. The top ends of the CO2 input risers do not penetrate the ground. The CO2 input risers are flower tube structures with multiple ventilation holes evenly distributed on the pipe body, and the CO2 input risers are arranged at equal intervals around the spray vertical wells.

[0007] As a further improvement of the present invention, the drilling depth of the spray vertical well does not exceed the burial depth of the aquiclude, or an artificial aquiclude is laid below the spray vertical well.

[0008] As a further improvement of the present invention, multiple layers of artificial aquicludes are evenly laid at equal intervals along the depth direction of the spray vertical well.

[0009] As a further improvement of the present invention, the burial depth of the bottom end of the CO2 input riser is greater than the bottom end depth of the spray vertical well.

[0010] As a further improvement of the present invention, the spray nozzles on the spray riser are atomizing nozzles, and the spraying directions of the nozzles are arranged along the radial direction of the spray shaft.

[0011] As a further improvement of the present invention, it further includes an electric control device, which includes a controller electrically connected to the water pump and an intermittent spray control circuit. The controller can control the water pump to open and close for spraying control at a set time interval.

[0012] As a further improvement of the present invention, it further includes an electric control device, which includes a controller, a flow sensor and a flow control circuit. The flow sensor is arranged at the output end of the control valve. The control valve includes a flow control valve. The controller is electrically connected to the control valve and the flow sensor respectively.

[0013] A CO2 sequestration process applicable to the gobi desert and saline-alkali land environment. Water is immersed into the soil through a spray shaft and a spray pipeline, and the captured CO2 is infiltrated into the soil through a CO2 input pipeline arranged underground, so as to realize the sequestration of CO2 in the form of salts underground.

[0014] For the gobi desert environment, first start the water pump to pump pressurized water into the spray riser. The spray water ejected from the nozzles sprays the inner wall of the spray shaft. The spray water soaks into the gobi desert soil and reacts with the inorganic ions contained in the gobi desert soil to form corresponding hydroxides. Then open the control valve to allow the CO2 capture source to supply CO2 into the CO2 input riser. The CO2 infiltrates into the gobi desert soil and reacts with the hydroxides to form carbonates, so as to realize the sequestration of CO2 in the form of carbonates underground.

[0015] For the saline-alkali land environment, start the water pump and open the control valve at the same time. While the water pump pumps pressurized water into the spray riser, the CO2 capture source supplies CO2 into the CO2 input riser. The spray water ejected from the nozzles sprays the inner wall of the spray shaft to soak the spray water into the saline-alkali land soil. At the same time, the CO2 in the CO2 input riser infiltrates into the gobi desert soil. The spray water and CO2 react with the carbonates contained in the saline-alkali land soil to form corresponding bicarbonates, so as to realize the sequestration of CO2 in the form of bicarbonates underground.

[0016] Compared with the prior art, the CO2 sequestration system and process applicable to the gobi desert and saline-alkali land environment can realize the sequestration of CO2 in the form of salts underground, can provide a new solution to the carbon sink problem in modern carbon cycle research, and also has the following advantages:

[0017] 1. In this process flow, no absorbent and catalyst are used, and the sequestration of CO2 is completely realized by using natural conditions. It is an environmentally friendly, pollution-free and low-cost CO2 storage method.

[0018] 2. In this process flow, laying the anti-seepage layer at a certain depth underground has two main functions: horizontally, the laying of the anti-seepage layer can make the water sprayed from the middle disperse more fully to both sides, so as to achieve a larger CO2 reaction absorption area, make full use of water resources without causing waste; vertically, it can prevent seepage and avoid polluting the groundwater of the gobi desert or other strata.

[0019] 3. In this process flow, only water, a non-polluting substance, is used, and a spraying device is adopted for water utilization. On the one hand, the spraying device can reduce water resource waste, make the water disperse more evenly in the underground soil layer, and avoid other changes caused by excessive humidity in a certain piece of land; on the other hand, the use of the spraying device enables the entire process not to lay too many pipelines, which can protect the underground environment of the gobi desert and saline-alkali land, and can also save costs during the laying process. Brief Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of a CO2 sequestration system applicable to the gobi desert and saline-alkali land environment. Detailed Implementation Modes

[0021] For the gobi desert environment, taking different types of gobi deserts distributed in the Hexi Corridor as an example:

[0022] The Gobi in Hexi is diverse in type and has a wide distribution range. Gravel Gobi, sandy gravel Gobi, soil Gobi, etc. are staggered in the east-west direction, with strong differences, and are distributed in obvious strips in the north-south direction. The soil of the Gobi in different sections of the corridor is different. The west is brown desert soil, the middle is gray-brown desert soil, and the east is gray desert soil, light brown calcium soil and gray calcium soil. Saline soil is widely distributed in low-lying areas, and the area gradually expands from east to west. The distribution area of ​​meadow soil decreases from east to west. Zonal vegetation is mainly composed of super-xerophytic shrubs and semi-shrubs. The soil pH value of most sample plots is between 7.0 and 8.0, which is slightly alkaline. This is because the parent rock of most Gobi-type soils is limestone, and the soil formation time is short. In addition, the sample points are located in arid and extremely arid areas, with little rainfall and large evaporation, and the soil salt is basically saturated. At the same time, a certain amount of calcium carbonate in the soil is also one of the reasons for its weak alkalinity, and some profiles contain a certain amount of calcium stratification. There are also a few plots with soil pH values ​​between 6.5 and 7.0, which are slightly acidic. The soil pH values ​​at different soil depths are generally stable and not very different. This shows that the Gobi soil has little difference from the surface to the deep layer in the vertical direction, and the soil properties are stable. In addition, during the formation of the Gobi, the loose rock bodies such as sandstone, silty mudstone and gravel deposited on the surface of the zone were continuously weathered and eroded by the sun and wind, turning into a large amount of debris. The organic matter content of these debris is extremely low. In addition, there is basically no vegetation on the surface of the Gobi or the vegetation is very sparse, and there are very few sources of soil organic matter such as plant roots and dead branches and leaves, so there is little accumulation of soil organic matter. Soil conductivity is an indicator for determining the content of water-soluble salts in soil. There are also large differences in soil conductivity at different depths in the same plot of some Gobi types. In general, the conductivity value tends to increase gradually with the increase of soil depth. The total salt content of the soil in the desalinated Gobi is between 2.69% and 32.87%. The average value is 11.15%, and the total salt content of other plots is between 0.05% and 4.27%, including: 0-2cm on the surface is between 0.06% and 1.74%, with an average value of 0.39%; 2-20cm is between 0.05% and 2.31%, with an average value of 0.69%; 20-40cm is between 0.06% and 2.43%, with an average value of 0.75%; 40-60cm is between 0.05% and 4.27%, with an average value of 0.81%. The total salt content of the soil generally increases with the increase of soil depth, and the average total salt content of the soil is 1.41%.

[0023] According to the soil classification standard and salinity classification, most of the soil in the typical Gobi area belongs to the sulfate-chloride type and chloride-sulfate type, and the rest belongs to the sulfate type. In addition, most of the soil profiles are slightly salinized soils, and a small part is moderately and severely salinized soils. In the salt ion composition of different types of Gobi soils, the main anion is SO4 2- and Cl- , SO4 2- The highest content reaches 3.75%, the lowest content is 0.005%, and the average content is 0.49%. Cl - The highest content is 5.18%, the lowest content is 0.008%, and the average value is 0.42%. In the soil, Cl - has good mobility and can be effectively recycled. Soil Cl - The content level is closely related to the terrain, precipitation, and degree of salinization. The content ranking of anions in each plot is SO4 2- > Cl - > HCO3 - > CO3 2- . The main cations are K + , Na + , Ca 2+ , Mg 2+ , K + + Na + The content is up to 3.70% at most, 0.009% at least, and 0.31% on average. Ca 2+ The highest content is 0.64%, the lowest content is 0.004%, and the average is 0.13%; Mg 2+ The highest content is 0.39%, the lowest content is 0.001%, and the average is 0.026%. The average content ranking of soil cations is K + + Na + > Ca 2+ > Mg 2+ .

[0024] Since the gobi desert soil contains more inorganic salt ions, many of which can react chemically with CO2 to achieve the effect of absorbing CO2. Taking Na + as an example, the reaction equation is as follows: 2Na + 2CO2 = Na2CO3 + CO. In addition, water can turn Na + into NaOH; a small amount of CO2 reacts with NaOH, and the ionic equation is: 2OH- + CO2 = CO3 2- + H2O; an excessive amount of CO2 reacts with NaOH, and the ionic equation is: OH - + CO2 = HCO3 - , so CO2 can be converted into carbonate and remain in the gobi desert soil. K + , Ca 2+ , Mg 2+ are the same. K +It turns into KOH under the action of water. When there is an excess of CO2, the reaction equation between the two is: 2KOH + CO2 = K2CO3 + H2O; when there is a small amount of CO2, the reaction equation between the two is: KOH + CO2 = KHCO3. Ca 2+ It turns into Ca(OH)2 under the action of water. When there is a small amount of CO2, CO2 + Ca(OH)2 = CaCO3 + H2O, and when there is an excess of CO2, CO2 + OH - = HCO3 - ; Mg 2+ It turns into Mg(OH)2 under the action of water. The reaction equation with CO2 is: 2Mg(OH)2 + CO2 = MgCO3 + 2H2O, and CO2 can also be converted into carbonate and remain in the gobi desert soil in the same way.

[0025] Taking the saline-alkali wetland at the estuaries of the Dagu River and Yanghe River in Jiaozhou Bay as an example for the saline-alkali land environment:

[0026] Coastal saline-alkali land is an important type of saline-alkali land globally. There is a large area of coastal saline soil distributed in China, with a total area of more than 100 hm 2 . Coastal saline-alkali wetlands have the characteristics of both marine and terrestrial ecosystems. Their special geographical location makes them an important link in connecting the carbon cycles of solid, liquid, and gaseous states. Under the influence of rainfall, tides, and human production and living activities, etc., the exchange reaction between coastal wetland saline soil and groundwater is frequent, resulting in regular salt accumulation and seawater desalination processes. Coastal wetland soil has two congenital conditions conducive to salt accumulation: one is being soaked by seawater for a long time and having sufficient salt sources; the other is flat terrain and poor drainage. At the same time, processes such as aquaculture or species invasion in coastal saline-alkali wetlands affect the original soil conditions in the muddy area, resulting in an increase in the degree of soil salinization in coastal wetlands.

[0027] The main cations in the soil of the saline-alkali wetland at the estuaries of the Dagu River and Yanghe River in Jiaozhou Bay are Na + and K + , followed by Ca 2+ and Mg 2 + ; the main anions are Cl - , followed by SO4 2- and HCO3 - , and the content of CO3 2- in the soil is almost zero. The total soil alkalinity is 0.68 - 0.99 g·kg -1 , and the ratio of HCO3 - to the total anion content in each soil sample is greater than 0.5%, and 91.67% of them are greater than 1%. Classified by alkalinity, the soil belongs to alkaline soil; classified by salinity, the soil belongs to sulfate saline soil or chloride saline soil.

[0028] Since saline-alkali soil is alkaline and contains a relatively large amount of carbonates, among which carbonates can react chemically with CO2 in an alkaline environment, thus achieving the effect of absorbing CO2. Taking the reaction of CaCO3 with CO2 as an example, its reaction mechanism is: CO2 + H2O = HCO3 - + H + ; CaCO3 + H + = Ca 2+ + HCO3 - ; CaCO3 + CO2 + H2O = Ca 2+ + 2HCO3 - . In this way, CO2 is stored underground in an inorganic form. Similarly, K2CO3 and Na2CO3 can also react with CO2 and store CO2 underground.

[0029] Based on the above principle, a CO2 sequestration system suitable for the Gobi Desert and saline-alkali land environment is constructed. As Figure 1 shown, the CO2 sequestration system suitable for the Gobi Desert and saline-alkali land environment includes a pressurized water input part and a CO2 input part.

[0030] The pressurized water input part includes a spray vertical well, a water pump, and a spray pipeline; the vertically arranged spray vertical well is drilled from the ground to the underground, and multiple spray vertical wells can be drilled at equal intervals; the input end of the water pump arranged on the ground is connected to the water tank, and the output end is connected to the spray pipeline; the spray pipeline includes spray risers communicated in each spray vertical well, and nozzles are provided on the spray risers.

[0031] The CO2 input part includes a CO2 input pipeline connected to the CO2 capture source through a control valve. The CO2 input pipeline includes multiple CO2 input risers arranged underground and extending vertically upward. To achieve a larger CO2 reaction absorption area, the buried depth of the bottom end of the CO2 input riser is greater than the bottom depth of the spray vertical well. The top end of the CO2 input riser does not penetrate the ground. The CO2 input riser is a perforated pipe structure with multiple ventilation holes evenly distributed on the pipe body, and the CO2 input risers are arranged at equal intervals around the spray vertical well.

[0032] For the Gobi Desert environment, when using this CO2 sequestration system, first start the water pump to pump pressurized water into the spray riser. The spray water ejected from the nozzle sprays the inner wall of the spray vertical well. The spray water soaks into the Gobi Desert soil and reacts with the inorganic ions contained in the Gobi Desert soil to form corresponding hydroxides; then open the control valve to allow the CO2 capture source to supply CO2 into the CO2 input riser. The CO2 seeps into the Gobi Desert soil and reacts with the hydroxides to form carbonates, realizing the sequestration of CO2 underground in the form of carbonates.

[0033] In view of the saline-alkali land environment, when the CO2 sequestration system is in use, start the water pump and simultaneously open the control valve. While the water pump pumps pressurized water into the spray riser, the CO2 capture source supplies CO2 into the CO2 input riser. The sprayed water sprays the inner wall of the spray shaft and infiltrates into the saline-alkali land soil. At the same time, the CO2 in the CO2 input riser infiltrates into the gobi soil. The sprayed water and CO2 react with the carbonate contained in the saline-alkali land soil to form the corresponding bicarbonate, realizing the sequestration of CO2 in the form of bicarbonate underground.

[0034] In order to prevent the sprayed water from seeping downward along the fissures and thus causing pollution to groundwater or other strata, as a further improvement scheme of the present invention, the driving depth of the spray shaft does not exceed the buried depth of the water-resistant stratum, or an artificial water-resistant layer is laid below the spray shaft.

[0035] In order to achieve the lateral infiltration of the sprayed water, thereby achieving a larger CO2 reaction absorption area and making full use of water resources, as a further improvement scheme of the present invention, multiple layers of artificial water-resistant layers are evenly spaced and laid along the depth direction of the spray shaft.

[0036] In order to achieve a better spray penetration effect of the sprayed water, as a further improvement scheme of the present invention, the nozzles on the spray riser are atomizing nozzles, and the spraying directions of the nozzles are arranged along the radial direction of the spray shaft.

[0037] In order to achieve a better spray water penetration effect and save water, as a further improvement scheme of the present invention, the CO2 sequestration system applicable to the gobi and saline-alkali land environments further includes an electric control device. The electric control device includes a controller electrically connected to the water pump and an intermittent spray control circuit. The controller can control the water pump to open and close at a set time interval to control the spray.

[0038] In order to control the supply flow rate of CO2 as needed, as a further improvement scheme of the present invention, the control valve includes a flow control valve.

[0039] In order to automatically control the supply flow rate of CO2, as a further improvement scheme of the present invention, the CO2 sequestration system applicable to the gobi and saline-alkali land environments further includes an electric control device. The electric control device includes a controller, a flow sensor, and a flow control circuit. The flow sensor is arranged at the output end of the control valve. The controller is electrically connected to the control valve and the flow sensor respectively. The controller can automatically control the CO2 flow rate supplied into the CO2 input riser according to the required CO2 supply flow rate.

[0040] The CO2 sequestration system and process applicable to the gobi and saline-alkali land environments can realize the sequestration of CO2 in the form of salt underground, and can provide a new solution for the carbon sink problem in modern carbon cycle research.

Claims

1. A CO2 sequestration system applicable to the gobi desert and saline-alkali land environments, characterized in that, It includes a pressure water input part and a CO2 input part; The pressure water input part includes a spray vertical shaft, a water pump and a spray pipeline; the vertically arranged spray vertical shaft is drilled from the ground to the underground, and multiple spray vertical shafts are evenly spaced; the input end of the water pump arranged on the ground is connected to the water tank, and the output end is connected to the spray pipeline; the spray pipeline includes spray risers communicated in each spray vertical shaft, and spray nozzles are arranged on the spray risers; The CO2 input part includes a CO2 input pipeline connected to the CO2 capture source through a control valve. The CO2 input pipeline includes multiple CO2 input risers arranged underground and extending vertically upward. The top end of the CO2 input riser does not penetrate the ground, and the buried depth of the bottom end of the CO2 input riser is greater than the buried depth of the bottom end of the spray vertical shaft. The CO2 input riser is a perforated pipe structure with multiple ventilation holes evenly distributed on the pipe body, and the CO2 input risers are evenly spaced around the spray vertical shaft.

2. The CO2 sequestration system applicable to the gobi desert and saline-alkali land environment according to claim 1, characterized in that, The drilling depth of the spray vertical shaft does not exceed the buried depth of the water-resistant stratum, or an artificial water-resistant layer is laid below the spray vertical shaft.

3. The CO2 sequestration system applicable to the gobi and saline-alkali land environments according to claim 1, characterized in that, Multiple layers of artificial water-resistant layers are evenly spaced along the depth direction of the spray vertical shaft.

4. The CO2 sequestration system applicable to the Gobi desert and saline-alkali land environment according to claim 1 or 2 or 3, characterized in that, The spray nozzles on the spray risers are atomizing nozzles, and the spraying directions of the nozzles are arranged along the radial direction of the spray vertical shaft.

5. The CO2 sequestration system applicable to the gobi desert and saline-alkali land environment according to claim 1 or 2 or 3, characterized in that, It also includes an electric control device. The electric control device includes a controller electrically connected to the water pump and an intermittent spray control circuit. The controller can control the water pump to start and stop for spraying at a set time interval.

6. The CO2 sequestration system applicable to the gobi desert and saline-alkali land environment according to claim 1 or 2 or 3, characterized in that, It also includes an electric control device. The electric control device includes a controller, a flow sensor and a flow control circuit. The flow sensor is arranged on the output end of the control valve. The control valve includes a flow control valve. The controller is electrically connected to the control valve and the flow sensor respectively.

7. A CO2 sequestration process applicable to the gobi desert and saline-alkali land environment based on the CO2 sequestration system applicable to the gobi desert and saline-alkali land environment as described in claim 1, characterized in that, Water is immersed into the soil through the spray vertical shaft and the spray pipeline, and the captured CO2 is infiltrated into the soil through the CO2 input pipeline arranged underground, so as to realize the underground storage of CO2 in the form of salt.

8. The CO2 sequestration process applicable to the Gobi Desert and saline-alkali land environment according to claim 7, characterized in that, For the gobi desert environment, first start the water pump to pump pressure water into the spray riser. The spray water ejected from the nozzle sprays the inner wall of the spray vertical shaft. The spray water infiltrates into the gobi desert soil and reacts with the inorganic ions contained in the gobi desert soil to form corresponding hydroxides; then open the control valve to allow the CO2 capture source to supply CO2 into the CO2 input riser. The CO2 infiltrates into the gobi desert soil and reacts with the hydroxides to form carbonates, so as to realize the underground storage of CO2 in the form of carbonates.

9. The CO2 sequestration process applicable to the gobi desert and saline-alkali land environment according to claim 7, characterized in that, For the saline-alkali land environment, start the water pump and open the control valve at the same time. While the water pump pumps pressure water into the spray riser, the CO2 capture source supplies CO2 into the CO2 input riser. The spray water ejected from the nozzle sprays the inner wall of the spray vertical shaft to make the spray water infiltrate into the saline-alkali land soil. At the same time, the CO2 in the CO2 input riser infiltrates into the gobi desert soil. The spray water and CO2 react with the carbonates contained in the saline-alkali land soil to form corresponding bicarbonates, so as to realize the underground storage of CO2 in the form of bicarbonates.

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