CN112811455B - Carbonation reactor and carbon dioxide capture system - Google Patents

Abstract

The present disclosure provides a carbon dioxide capture system, which includes a carbonation reactor, a calciner, and a hydration reactor connected together. Add high-temperature metal hydroxide from the top of the carbonation reactor, and pass low-temperature flue gas from the bottom of the carbonator, through the carbonation reactor with cyclone dust collection unit, the high-temperature metal oxide and low-temperature flue gas Gas heat exchange to omit the heater for heating the flue gas and the cooler for controlling the carbonation reactor.

Description

Carbonation Reactor and Carbon Dioxide Capture System

technical field

The present disclosure relates to carbon dioxide capture systems, and more particularly to the carbonation reactors employed therein.

Background technique

The global energy demand continues to grow, and it is estimated that the future will still rely on the supply of fossil energy. The International Energy Agency emphasized in the "Energy Technology Outlook 2010" (International Energy Agency, 2010) that in order to maintain energy security, promote economic development, and reduce energy consumption. In relation to carbon dioxide emissions, efforts should be made to improve power generation efficiency, energy use efficiency, and the development of carbon capture and storage technologies. In line with the world trend, many countries have set policy goals for reducing carbon dioxide emissions. In order to achieve this goal, in terms of energy, in addition to improving energy efficiency, developing clean energy, and ensuring a stable energy supply, it is necessary to use carbon dioxide capture, storage, and reuse technologies when it is still unavoidable to continue using fossil fuels. To effectively slow down the deterioration of the greenhouse effect.

Most current calcium loop carbon dioxide capture processes use a two-stage cycle system of carbonation reactor and calciner to capture carbon dioxide and regenerate the sorbent. However, although the reaction of the two-stage circulation system is simple, the reaction rate of CaO and _CO2 is slow, and the efficiency in treating a large amount of waste gas is poor.

In order to solve the above problems, some literatures propose a carbon dioxide capture system comprising a carbonation reactor, a calciner, and a three-stage circulation system of a hydration reactor. Although this carbon dioxide capture system is relatively complex, the reaction rate between calcium hydroxide and carbon dioxide is relatively fast, which can greatly increase the capture efficiency of carbon dioxide. However, this system faces new problems when it is scaled up to an industrial scale. For example, the reaction in the carbonation reactor is an exothermic reaction, so a cooler is required to control the temperature to avoid overheating of the carbonation reactor and cause industrial safety problems. On the other hand, the temperature of the carbon dioxide-containing flue gas introduced into the carbonation reactor at the beginning is too low to effectively react with calcium hydroxide, and additional heating of high carbon dioxide is required. In short, the carbonation reactor needs to heat the flue gas containing carbon dioxide and cool the flue gas and adsorbent after the carbonation reaction. These necessary devices and operations will consume energy. On the other hand, the hydration reactor needs to use superheated steam to react with calcium oxide. The step of generating superheated steam is to first heat water to generate saturated steam, and then heat saturated steam to form superheated steam. These heating steps require additional heating equipment, ie further energy consumption and increased CO2 emissions.

To sum up, a new system design is urgently needed to overcome the problems caused by the aforementioned three-stage circulation system.

Contents of the invention

The object of the present invention is to provide a newly designed carbon dioxide capture system to basically overcome the above-mentioned problems caused by the three-stage circulation system in the prior art.

The carbonation reactor provided by an embodiment of the present disclosure includes: a plurality of connected and vertical cyclone dust collection units and a plurality of risers, wherein each cyclone dust collection unit includes a side feed port and a top exhaust port , and a discharge port at the bottom, among two adjacent cyclone dust collection units, the discharge port of the upper cyclone dust collection unit is connected to the lower ascending pipe, and the ascending pipe is connected to the lower cyclone dust collecting unit unit, and the feed port of the cyclone dust collection unit on the upper side is also connected to the exhaust port of the cyclone dust collection unit on the lower side through the ascending pipe on the second upper side, which is connected to the cyclone dust collection unit on the second upper side The feed port of the dust unit receives the metal hydroxide through the second upper riser, and the feed port of the lowermost cyclone dust collection unit receives the flue gas through the lower riser, and the temperature of the metal hydroxide greater than the temperature of the flue gas, wherein the metal hydroxide in each of the cyclone dust collection units falls from the feed port toward the discharge port, and exchanges heat with the reverse flue gas and reacts to form the powder of the metal carbonate, by The flue gas with a lower carbon dioxide concentration is discharged from the exhaust port, and the metal carbonate and unreacted metal hydroxide are discharged from the discharge port.

In one embodiment, the temperature of the flue gas received by the lowermost riser is between 50°C and 200°C and provided to the feed inlet of the lowermost cyclone dust collection unit, and the feed inlet of the second upper riser is The temperature of the metal hydroxide received by the feed port is between 200°C and 500°C and provided to the feed port of the cyclone dust collection unit on the second upper side.

In one embodiment, the temperature after the reaction and heat exchange between the metal hydroxide in the carbonation reactor and the reverse flue gas is between 350°C and 650°C.

A carbon dioxide capture system provided in an embodiment of the present disclosure includes: a carbonation reactor, including: a plurality of connected and vertical cyclone dust collection units and a plurality of risers, wherein each cyclone dust collection unit includes a side feed port , the exhaust port at the top, and a discharge port at the bottom. Among the two adjacent cyclone dust collection units, the discharge port of the upper cyclone dust collection unit is connected to the lower riser pipe, and the riser pipe is connected to the The feed port of the cyclone dust collection unit on the lower side, and the feed port of the cyclone dust collection unit on the upper side is also connected to the exhaust port of the cyclone dust collection unit on the lower side through the ascending pipe on the second upper side, which is connected to The feed inlet of the next upper cyclone dust collection unit receives the metal hydroxide through the second upper riser pipe, and the feed inlet of the lowermost cyclone dust collection unit receives the flue gas through the lowermost riser pipe, and The temperature of the metal hydroxide is greater than the temperature of the flue gas, wherein the metal hydroxide in each of the cyclone dust collection units falls from the feed port toward the discharge port, and exchanges heat with the reverse flue gas and reacts to form metal carbonic acid The powder of the compound, the flue gas with a lower carbon dioxide concentration is discharged from the exhaust port, and the metal carbonate and unreacted metal hydroxide are discharged from the discharge port; the calciner is connected to the lowermost side of the carbonation reactor The discharge port of the cyclone dust collection unit is used to receive the powder of metal carbonate, and the metal carbonate is calcined to form metal oxide and high temperature and high concentration of carbon dioxide; the hydration reactor is connected to the calciner to receive the metal oxide, And the metal oxide is reacted with superheated steam to form metal hydroxide, wherein the feed port of the cyclone dust collection unit on the second upper side of the carbonation reactor is connected to the hydration reactor to receive the metal hydroxide from the hydration reactor.

In one embodiment, the temperature of the flue gas received by the lowermost riser is between 50°C and 200°C and provided to the feed inlet of the lowermost cyclone dust collection unit, and the feed inlet of the second upper riser is The temperature of the metal hydroxide received by the feed port is between 200°C and 500°C and provided to the feed port of the cyclone dust collection unit on the second upper side.

In one embodiment, the temperature after the reaction and heat exchange between the metal hydroxide in the carbonation reactor and the reverse flue gas is between 350°C and 650°C.

In one embodiment, the temperature for calcining the metal carbonate in the calciner is between 850°C and 1200°C.

In one embodiment, the carbon dioxide produced by the calciner is used for heat exchange with saturated steam to form superheated steam for the hydration reactor.

In one embodiment, the high-temperature and high-concentration carbon dioxide produced by the calciner is used to indirectly heat the carbon dioxide-containing flue gas passed into the carbonation reactor.

In one embodiment, the reaction temperature of the metal oxide and the superheated steam in the hydration reactor is between 200°C and 500°C.

Compared with the prior art, the carbon dioxide capture system of the present invention has the advantage that: by including the connected carbonation reactor, calciner, and hydration reactor, the carbon dioxide capture system of the present invention adds high-temperature carbon dioxide from the top of the carbonation reactor. Metal hydroxide, and the low-temperature flue gas is introduced from the bottom of the carbonator, through the carbonation reactor containing the cyclone dust collection unit, the high-temperature metal oxide and the low-temperature flue gas are heat-exchanged, so that the heating of the flue gas can be omitted heaters and coolers to control the carbonation reactor.

Description of drawings

FIG. 1 is a schematic diagram of a carbon dioxide capture system in an embodiment of the present disclosure;

2 is a schematic diagram of a carbon dioxide capture system in an embodiment of the present disclosure;

3 is a schematic diagram of a carbonation reactor in an embodiment of the present disclosure;

Fig. 4 is a schematic diagram of a cyclone dust collection unit in an embodiment of the present disclosure;

5 is a schematic diagram of a carbon dioxide capture system in an embodiment of the present disclosure;

Among them, the symbol description:

C0, C1, C2, C3, C4 cyclone dust collection unit

L0, L1, L2, L3, L4 Riser

100, 200 Carbon dioxide capture system

101, 101' flue gas

105 high concentration carbon dioxide

110 carbonation reactor

120 calciner

130 Hydration Reactor

131 water

133 Saturated steam

135, 137 superheated steam

140 heater

150 cooler

160 burner

170 Boiler

180 superheater

190 heat exchanger

410 feed port

420 exhaust port

430 Dock.

Detailed ways

FIG. 1 is a schematic diagram of a carbon dioxide capture system 100 according to an embodiment of the present disclosure. It has a carbonation reactor 110 , a calciner 120 , and a hydration reactor 130 connected thereto. In this design, the reaction temperature (350°C to 650°C) of the carbonation reactor 110 is higher than the temperature of the flue gas and carbon dioxide-containing flue gas 101 before treatment. Therefore, it is necessary to additionally set up a heater 140 to heat the flue gas 101, and then pass the flue gas 101 into the carbonation reactor 110, so that the carbon dioxide in the flue gas 101 reacts with metal hydroxide (such as calcium hydroxide), and then reacts in the carbonation reaction The device 101 discharges the treated flue gas 101'. The carbon dioxide concentration of the treated flue gas 101' is lower than that of the flue gas before treatment, but its temperature is higher than that of the flue gas 101 before heating. However, the reaction of metal hydroxides with carbon dioxide to form metal carbonates (such as calcium carbonate) with water is exothermic. In order to prevent the temperature of the carbonation reactor 110 from being too high, an additional cooler 150 is required to prevent the carbonation reactor 110 from being overheated. It can be understood that the heater 140 generates heat by burning fuel, which not only consumes energy but also produces additional carbon dioxide. In other words, the heater 140 used to treat the carbon dioxide in the flue gas 101 will generate additional carbon dioxide to be treated. In addition, regardless of the mode of the cooler 150 (such as air-cooled or water-cooled), circulating the cooling medium also requires additional energy. In short, the heater 140 and the cooler 150 consume extra energy, generate carbon dioxide, and increase equipment costs.

Next, the metal carbonate (such as calcium carbonate) produced by the carbonation reactor 110 is introduced into the calciner 120, and the metal carbonate (such as calcium carbonate) is thermally decomposed into metal oxide (such as calcium oxide) and high-concentration carbon dioxide 105 (carbon dioxide Concentration>80%). However, the thermal decomposition of metal carbonates into metal oxides in the calciner 120 and the reaction temperature of the high-concentration carbon dioxide 105 are high (850° C. to 1200° C.), so an additional combustion furnace 160 is required to heat the calciner 120 . On the other hand, the high-concentration carbon dioxide 105 produced by the calciner 120 has an extremely high temperature and needs to be cooled before further processing. If an extra cooler (not shown) is used to cool the high-concentration carbon dioxide 105 , the cost of the extra cooler and extra energy consumption will be required. If the high-temperature high-concentration carbon dioxide 105 is allowed to cool naturally, it is time-consuming and requires large-volume storage equipment.

Next, the metal oxide (such as calcium oxide) produced by the calciner 120 is introduced into the hydration reactor 130 to make the metal oxide (such as calcium oxide) react with water/steam to form metal hydroxide (such as calcium hydroxide). The hydration reactor 130 may be a solution-type hydration reactor or a steam-type hydration reactor. If the metal hydroxide (such as calcium hydroxide) produced by the solution-type hydration reactor (not shown) is dissolved in water, additional water removal is required to obtain dry metal hydroxide powder, which consumes extra energy. The method for forming the superheated steam 135 used in the steam-type hydration reactor 130 is as follows: use the boiler 170 to heat the water 131 to form the saturated steam 133, then use the superheater 180 to heat the saturated steam 133 to form the superheated steam 135, and then introduce the superheated steam 135 into the hydration reaction 130 to react with metal oxides to form metal hydroxides. Both the boiler 170 and the superheater 180 are necessary energy-consuming equipment for generating the superheated steam 135 . Since the reaction of metal oxide and water to form metal hydroxide is an exothermic reaction, it is necessary to discharge higher temperature superheated steam 137 (higher than superheated steam 135) to maintain the temperature of hydration reactor 130 at an appropriate reaction temperature ( 200°C to 500°C). Next, the metal hydroxide produced in the hydration reactor 130 and a small amount of unreacted metal oxide are introduced into the carbonation reactor 110 . In the carbonation reactor 110 , metal oxides (such as calcium oxide) can also react with carbon dioxide to form metal carbonates (such as calcium carbonate), but the required reaction temperature is higher (such as higher than 550° C.).

In summary, when the above system is scaled up to industrial applications, the carbonation reactor 110, the calciner 120, and the hydration reactor 130 all need additional heaters and/or coolers (such as the heater 140, cooler 150 , combustion furnace 160, boiler 170, and superheater 180) to achieve the required reaction temperature or reactants, will increase equipment costs and energy consumption and increase additional carbon dioxide.

Another embodiment of the present disclosure provides another carbon dioxide capture system 200 , as shown in FIG. 2 . In the carbonation reactor 110, high-temperature metal hydroxide powder (about 200°C to 500°C) is placed from the top, and low-temperature carbon dioxide-containing flue gas 101 (about 50°C to 200°C) is introduced from the bottom , make the flue gas 101 containing low temperature and carbon dioxide and high temperature metal hydroxide powder (may contain a small amount of metal oxide) generate heat exchange and react to form metal carbonate. For example, the upper part of the carbonation reactor 110 is a reaction zone, that is, metal hydroxide powder (possibly containing a small amount of metal oxide) reacts with carbon dioxide in the flue gas 101 to form metal carbonate. The lower part of the carbonation reactor 110 is a heat exchange area, that is, the high-temperature metal carbonates exchange heat with the low-temperature flue gas 101 containing carbon dioxide. Further explanation is as follows, the metal carbonates fall to the bottom of the carbonation reactor 110 due to gravity, and contact the rising flue gas 101 to generate heat exchange, that is, the temperature of the metal carbonates decreases, while the temperature of the flue gas 101 increases. Finally, the carbon dioxide concentration of the treated flue gas 101' is reduced (can be reduced to no carbon dioxide) and discharged from the top of the carbonation reactor 110. Through the above design, the heater 140 for heating the flue gas 101 and the cooler 150 for cooling the carbonation reactor 110 in FIG. 1 can be omitted.

In one embodiment, the carbonation reactor 110 includes a plurality of connected and vertical cyclone dust collection units and a plurality of risers, as shown in FIG. 3 . It should be noted that the carbonation reactor 110 in FIG. 3 has five cyclone dust collection units (such as cyclone dust collection units C0 to C4) and risers (such as risers L0 to L4), but the carbonation reactor 110 can be There are more or less cyclone dust collection units and risers, for example, 3 to 10 cyclone dust collection units and 3 to 10 risers, depending on actual needs. Each cyclone dust collection unit includes a side feed port 410 , a top exhaust port 420 , and a bottom discharge port 430 , as shown in FIG. 4 .

In Fig. 3 and Fig. 4, among two adjacent cyclone dust collection units (such as cyclone dust collection units C1 and C2), the discharge port 430 of the upper side cyclone dust collection unit (such as C1) is connected to the lower one. The riser (such as L2) is connected to the feed inlet 410 of the lower cyclone dust collection unit (such as C2) through the riser. In detail, this is the direction of solid travel, as shown by the dotted line in Figure 3. In addition, the feed inlet 410 of the upper cyclone dust collection unit (such as C1 ) is connected to the riser pipe (such as L1 ) of the exhaust outlet 420 of the lower cyclone dust collection unit (such as C2 ). In detail, this is the traveling direction of the gas, as shown by the solid line in FIG. 3 . Further, the dotted line is the traveling direction of the solid, and the solid line is the traveling direction of the gas, and the solid and the gas travel in the same riser. Taking Fig. 3 as an example, the carbon dioxide-containing flue gas 101 is first provided to the feed port 410 of the lowermost cyclone dust collection unit C4 through the riser L4, and its traveling direction in the cyclone dust collection unit C4 is shown in Fig. 4 , first whirling downwards, then blowing upwards out of the exhaust port 420 of the cyclone dust collection unit C4, and then entering the feed port 410 of the cyclone dust collection unit C3 through the riser pipe L3. Similar to the above, the flue gas 101 is sequentially blown through the cyclone dust collection unit C3, the ascending pipe L2, the cyclone dust collection unit C2, the ascending pipe L1, the cyclone dust collection unit C1, the ascending pipe L0, and the cyclone dust collection unit C0, and finally processed The final flue gas 101' is discharged from the exhaust port of the cyclone dust collection unit. When the carbon dioxide-containing flue gas 101 leaves the exhaust port 420 of the cyclone dust collection unit C2, the high-temperature metal hydroxide powder (such as Ca(OH) ₂ , such as metal hydrogen from the hydration reactor 130 can be passed through the riser L1 Oxide powder, which may contain a small amount of metal oxide such as calcium oxide) and the powder (as described below) from the discharge port 430 of the cyclone dust collection unit C0 are blown into the cyclone dust collection unit C1 together to make the cyclone dust collection The metal hydroxide in the unit C1 falls from the feed port 410 toward the discharge port 430, and reacts with the carbon dioxide-containing flue gas 101 that is swirled downward and then sucked upward (ie reverse direction) to form metal carbonate. In this way, the treated flue gas 101' can be discharged from the exhaust port 420 of the cyclone dust collection unit C1. The carbon dioxide concentration of the treated flue gas 101' is lower than that of the flue gas 101 before entering the carbonation reactor, and the metal carbonate and unreacted metal carbonates are discharged from the discharge port 430 of the cyclone dust collection unit C1 of metal hydroxides.

The flue gas 101' discharged from the cyclone dust collection unit C1 may contain a small amount of powder, so it enters the feed port 410 of the cyclone dust collection unit C0, and a small amount of powder is discharged from the discharge port 430 of the cyclone dust collection unit C0. As shown in Figures 3 and 4, the powder discharged from the discharge port 430 of the cyclone dust collection unit C0 can be sent into the cyclone through the riser L1 with the carbon dioxide-containing flue gas 101 discharged from the exhaust port 420 of the cyclone dust collection unit C2. Dust collection unit C1. The powder discharged from the discharge port 430 of the cyclone dust collection unit C1 sends the flue gas 101 discharged from the cyclone dust collection unit C3 to the cyclone dust collection unit C2 through the riser L2, and the reaction is the same as described above. With the order of the metal hydroxide powder from the ascending pipe L1→cyclone dust collecting unit C1→rising pipe L2→cyclone dust collecting unit C2→rising pipe L3→cyclone dust collecting unit C3→rising pipe L4→cyclone dust collecting unit C4 , and finally the solid composition discharged from the bottom discharge port 430 of the cyclone dust collection unit C4 is mainly metal carbonate. On the other hand, the flue gas 101 containing carbon dioxide flows from the ascending pipe L4→cyclone dust collecting unit C4→rising pipe L3→cyclone dust collecting unit C3→rising pipe L2→cyclone dust collecting unit C2→rising pipe L1→cyclone dust collecting unit C1 →The sequence of rising pipe L0→cyclone dust collection unit C0, finally discharges the treated flue gas 101' with low carbon dioxide concentration from the exhaust port 420 at the top of the cyclone dust collection unit C0, which achieves the purpose of carbon dioxide capture. It is worth noting that in the upper cyclone dust collection units (such as C1 and C2), the powder is mainly composed of metal hydroxides, so the reaction of metal hydroxides and carbon dioxide to form metal carbonates is mainly carried out. In the lower cyclone dust collection units (such as C3 and C4), the powder is mainly composed of metal carbonates, so the heat exchange between the powder and the carbon dioxide-containing flue gas 101 is mainly carried out, that is, the temperature and temperature of the carbon dioxide-containing flue gas 101 are increased. Lower the temperature of the powder. However, it is understandable that there may still be heat exchange in the upper cyclone dust collection unit. For example, when the temperature of the metal carbonate produced by the exothermic reaction is higher than the temperature of the flue gas 101, the flue gas 101 will produce with the metal carbonate. The heat exchange increases the temperature of the flue gas 101 and decreases the temperature of the calcium carbonate. On the other hand, if the powder in the lower cyclone dust collection unit contains metal hydroxide, it may also react with carbon dioxide in the flue gas 101 to form metal carbonate. In addition, the length of the lower riser pipes (such as L4 and L3) is longer than that of the upper riser pipes (such as L0 and L1), so that the upper cyclone dust collection units (such as C1 and C2) mainly collect metal hydrogen Oxides react with carbon dioxide to form metal carbonates, and the lower cyclone dust collection units (such as C3 and C4) are mainly designed for heat exchange between flue gas 101 and powder.

The positions of the cyclone dust collection units C0, C1, C2, C3, and C4 in FIG. 3 are just examples, and those skilled in the art can adjust the relative positions of the above cyclone dust collection units according to actual needs. On the other hand, the cyclone dust collection units C0, C1, C2, C3, and C4 in Fig. 3 have similar sizes, but actually different cyclone dust collection units C0, C1, C2, C3, and C4 may also have different sizes, It depends on the design requirements.

In one embodiment, the mass flow rate of the metal hydroxide (here calcium hydroxide) from the hydration reactor 130 is 2.15 ton/h for capturing 0.16 ton/h of carbon dioxide. Set the temperature of the carbon dioxide-containing flue gas 101 at 100°C, 150°C, and 200°C, and calculate the temperatures of the cyclone dust collection unit and the riser as shown in Table 1. It can be seen from Table 1 that when the temperature of the flue gas 101 is fed higher, the temperature of the more risers and the more cyclone dust collection units can reach the carbonation temperature of calcium hydroxide (for example, higher than 300 ° C) and the carbonation temperature of calcium oxide carbonation. The temperature of melting (for example, higher than 550°C).

Table 1

Returning to Fig. 2, the metal carbonates formed above are sent to the calciner 120 for high-temperature calcination, so that the metal carbonates are decomposed into metal oxides and high-temperature high-concentration carbon dioxide 105, and the high-temperature high-concentration carbon dioxide 105 is introduced into the heat exchanger 190 , to exchange heat with saturated steam 133 to form superheated steam, as described below. On the other hand, the high-temperature high-concentration carbon dioxide 105 can be introduced into the high-temperature combustion furnace 160 to increase the mass flow rate of high-temperature flue gas to facilitate the operation of the pure oxygen calciner 120 and improve the powder delivery efficiency of the calciner 120 .

Next, the metal oxides produced in the calciner 120 are introduced into the steam-type hydration reactor 130 to react the metal oxides with water to form metal hydroxides. The formation method of the superheated steam 135 used by the steam-type hydration reactor 130 is as follows: use the boiler 170 to heat the water 131 to become the saturated steam 133, and then use the heat exchanger 190 to make the saturated steam 133 generate heat exchange with the high-temperature high-concentration carbon dioxide 105, reducing the The temperature of high-temperature high-concentration carbon dioxide 105 is increased, and the temperature of saturated steam 133 is increased to form superheated steam 135 . The heat exchanger 190 can save the energy consumption and additional carbon dioxide generated for heating the saturated steam 133 , and save the equipment, time, energy consumption and additional carbon dioxide generated for cooling the high-temperature and high-concentration carbon dioxide 105 generated by the calciner 120 .

Superheated steam 135 is then introduced into the hydration reactor 130 to react with the metal oxides to form metal hydroxides. Since the reaction of metal oxide and water to form metal hydroxide is an exothermic reaction, it is necessary to discharge higher temperature superheated steam 137 (higher than superheated steam 135) to maintain the temperature of hydration reactor 130 at an appropriate reaction temperature ( 200°C to 500°C). In this embodiment, the superheated steam 137 can be sent back to the heat exchanger 190, so as to reduce the saturated steam 133 required by the boiler 170, and also reduce the thermal energy required to form the superheated steam 135 from the saturated steam 133 in the heat exchanger 190 . The metal hydroxide produced in the hydration reactor 130 is then introduced into the carbonation reactor 110 .

As shown in Figure 5, the high-temperature high-concentration carbon dioxide 105 produced by the calciner 120 can also be used to heat (non-mix) the flue gas 101 passing into the carbonation reactor 110, so as to reduce the carbonation reactor 110. Number of heat exchange cyclone units required for oxide heat exchange.

In the above embodiments, the metal carbonate may be placed into the calciner 120 , the metal oxide into the hydration reactor 130 , or the metal hydroxide into the top of the carbonation reactor 110 initially. In some embodiments, metal carbonates to the calciner 120, metal oxides to the hydration reactor 130, and metal hydroxides to the top of the carbonation reactor 110 may be replenished during the process. In the above embodiments, the metal of the metal carbonate, metal hydroxide, and metal oxide may be calcium. In other embodiments, the metal of the metal carbonate, metal hydroxide, metal oxide may be magnesium or other suitable metal.

The effects of Ca(OH) ₂ and CaO on converting different proportions of CO2 at different temperatures are shown in Table 2. As shown in Table 2, the carbonation conversion rate of Ca(OH) ₂ is 60% at 350°C, while the carbonation conversion rate of CaO increases significantly when the reaction temperature is higher than 500°C. In addition, the carbonation conversion rate of Ca(OH) ₂ is relatively high, the operating temperature range is relatively wide, and the overall reaction program design is more flexible, and the carbon dioxide concentration will not affect the results. In short, Ca(OH) ₂ is better than CaO for capturing carbon dioxide.

Table 2

To sum up, the present application provides a novel carbon dioxide capture system, which can effectively reduce energy consumption and additionally generated carbon dioxide.

Although the present disclosure has been disclosed above with several embodiments, it is not intended to limit the present disclosure. Anyone with ordinary knowledge in the technical field may make any changes and modifications without departing from the spirit and scope of the present disclosure. Retouching, so the scope of protection of this disclosure should be defined by the scope of the appended patent application.

Claims (2)

1. A carbon dioxide capture system comprising a three-stage circulation system, comprising: Carbonation reactors, including: Connected and upright multiple cyclone dust collection units and multiple risers, Each of the cyclone dust collection units includes a side feed port, a top exhaust port, and a bottom discharge port, Among two adjacent cyclone dust collection units, the discharge port of the upper cyclone dust collection unit is connected to the lower riser pipe, and the riser pipe is connected to the feed inlet of the lower cyclone dust collection unit, and the upper The feed inlet of the cyclone dust collection unit on the side is also connected to the exhaust port of the cyclone dust collection unit on the lower side through the ascending pipe on the second upper side, The feed inlet connected to the cyclone dust collection unit on the second upper side receives the metal hydroxide with a temperature between 200°C and 500°C through the rising pipe on the second upper side, and the cyclone dust collection unit on the lowermost side The feed port of the feed port receives flue gas at a temperature between 50°C and 200°C through the lowermost riser, and the temperature of the metal hydroxide is higher than the temperature of the flue gas, Wherein the metal hydroxide in each of the cyclone dust collection units falls from the feed port toward the discharge port, and exchanges heat with the reverse flue gas and heats up at 350 to 650°C The temperature between them reacts to form the powder of metal carbonate, the flue gas with lower carbon dioxide concentration is discharged from the exhaust port, and the metal carbonate and unreacted metal hydroxide are discharged from the discharge port; A calciner connected to the discharge port of the cyclone dust collection unit on the lowermost side of the carbonation reactor to receive the powder of metal carbonate, and calcinate the metal carbonate at a temperature between 850°C and 1200°C to obtain Formation of metal oxides and high temperature and high concentration of carbon dioxide, a hydration reactor connected to the calciner to receive the metal oxide and react the metal oxide with superheated steam at a temperature between 200°C and 500°C to form a metal hydroxide, Wherein the high-temperature and high-concentration carbon dioxide produced by the calciner is supplied to a heat exchanger for heat exchange with saturated steam to form the superheated steam used in the hydration reactor, and introduced into a high-temperature combustion furnace to raise the temperature and then supplied to the The calciner is used to improve the powder conveying efficiency of the calciner, or to heat the flue gas passing into the carbonation reactor, Wherein the feed inlet of the cyclone dust collection unit on the second upper side of the carbonation reactor is connected to the hydration reactor to receive the metal hydroxide from the hydration reactor. 2. The carbon dioxide capture system comprising a three-stage circulation system as claimed in claim 1, wherein the carbon dioxide produced by the calciner is used to heat the flue gas passed into the carbonation reactor.

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