KR102264811B1 - Reaction Rate Improvement Method of Chemical Looping Combustion System and Start-up Procedure Using Thereof - Google Patents

Abstract

The present invention relates to a chemical roofing combustion system with improved reaction rate, and more particularly, to an air reactor in which oxygen delivery particles are oxidized by reacting with air supplied by an air supply means; a fuel reactor to which oxygen transfer particles oxidized in the air reactor are supplied, fuel supplied by a fuel supply means is burned to reduce the oxidized oxygen transfer particles, and the reduced oxygen transfer particles are supplied to the air reactor; an air reactor preheating means for preheating each of the air reactor and the fuel reactor to a preset temperature before driving the combustion system, and a fuel reactor preheating means; hydrogen supply means for supplying hydrogen gas into the fuel reactor before driving the combustion system; and controlling the air reactor preheating means and the fuel reactor preheating means so that the air reactor and the fuel reactor reach a set temperature, and the hydrogen supply means so that the solid conversion rate of the oxygen transfer particles in the fuel reactor reaches a set conversion rate value. It relates to a chemical looping combustion system having an improved reaction rate, comprising: a control unit for controlling.

Description

Reaction Rate Improvement Method of Chemical Looping Combustion System and Start-up Procedure Using Thereof

The present invention relates to a chemical looping combustion system with improved reaction rate and a driving method of the chemical looping combustion system.

Among the various technologies for capturing and separating carbon dioxide from mass emission sources, the capture technology during combustion (pure oxygen combustion technology), which emits only a high concentration of carbon dioxide during the combustion process, is a separate separation technology because the combustor itself emits a high concentration of _{CO 2 It has the advantage of being able to fundamentally separate CO 2} without a facility, and can be mainly used as a facility for retrofit of a new power plant or an existing power plant.

On the other hand, unlike the conventional pure oxygen combustion technology, which separates oxygen in the air and supplies it to the combustor, the chemical looping combustion system (or medium circulation combustion system) uses particle-state metal oxide to generate oxygen in the air in one reactor. It is absorbed and moved to another reactor to prevent mixing of nitrogen in the air and carbon dioxide generated by combustion through the separation combustion reaction that reacts fuel and oxygen, and next-generation combustion that does not require a separate facility to separate oxygen it's technology

1 shows the basic concept of a chemical roofing combustion system. The entire system is composed of an air reactor 10 and a fuel reactor 40. In the air reactor, as shown in Equation (1), the metal component (M) contained in the oxygen transfer particle 1 is oxidized by oxygen in the air to form a metal. Oxide (MO) is formed, the oxidized oxygen transfer particles are transferred to the fuel reactor 40, and in the fuel reactor 40, the metal oxide (MO) is converted into fuel (natural gas, coal, syngas) as shown in Equation (2). , biomass, etc.), the metal oxide is reduced back to the metal component, and _{only CO 2} , H ₂ O is generated. The oxygen transfer particles 1 reduced in the fuel reactor 40 are recycled to the air reactor 10 and the above process is repeated.

Oxidation reaction: 2M _x O _{y -1} + O ₂ → 2M _x O _y (1)

Reduction reaction: (2n+m)M _x O _y + C _n H _2m → (2n+m)M _x O _{y -1} +mH ₂ O+nCO ₂ (2)

In the air reactor 10 of the chemical roofing combustion system, since the gas-solid reaction occurs in the absence of a flame, the generation of thermal-NOx can be minimized, and a separate air separation facility is not required, and in the fuel reactor 40 Since the emitted gases are only CO ₂ and H ₂ O, condensing and separating moisture has an advantage in that high-concentration CO _{2 can be fundamentally separated without a separate CO 2 separation facility.}

On the other hand, considering methane, which is the main component of natural gas among fuels used in the chemical roofing combustion system, and considering the case where the main component of oxygen transfer particles is Ni (nickel), Equations (1) and (2) are It is expressed as Equations (3) and (4), and the oxidation reaction occurring in the air reactor 10 is an exothermic reaction whereas the reduction reaction occurring in the fuel reactor 40 is an endothermic reaction.

Oxidation reaction (exothermic reaction): 2Ni + O ₂ → 2NiO (3)

Reduction reaction (endothermic reaction): 4NiO + CH ₄ → 4Ni + CO ₂ + 2H ₂ O (4)

The oxidation reaction of the chemical roofing combustion system depends on the composition of the oxygen transfer particles, but when nickel-based oxygen transfer particles are used, the oxidation reaction may occur at a temperature of ^{600 o C or higher.}

On the other hand, the reduction reaction may also ^{occur at a temperature of 600 o} C or higher, but when the fuel reactor 40 is operated at a low temperature, the fuel conversion rate (fuel conversion) indicating the fuel actually used for combustion among the injected fuels is low. a low combustion efficiency of fuel, after combustion of the total fuel gas injected CO ₂ indicating the selected amount of gas discharged from the CO ₂ form also (CO ₂ selectivity) due to low source separation of high-concentration CO ₂ is not possible.

2A is a graph showing the fuel conversion rate according to the reduction reaction temperature of the oxygen transfer particles for each of the three particles in the fuel reactor of the chemical looping combustion system, and FIG. 2B is the oxygen transfer particles for each of the three particles in the fuel reactor of the chemical looping combustion system. shows a graph of the fuel conversion rate according to the reduction reaction temperature of _{That is, in FIGS. 2a and 2b, the fuel conversion rate and CO 2} selectivity according to the temperature change of the fuel reactor 40 for three types of Ni-based oxygen transfer particles (SDN70, N018-R2, N018-R4) were shown. (Source: Hana Kim, Jung-Hwan Kim, Joo-Young Yoon, Doyeon Lee, Jeom-In Baek, Ho-Jung Ryu, “Selection of the Best Oxygen Carrier for Chemical Looping Combustion in a Bubbling Fluidized Bed Reactor”, Clean Technology , Vol. 24, No. 1, pp. 63-69 (2018).)

As shown in FIGS. 2A and 2B , in the temperature range of 750 to 900° C., as the reaction temperature of all three oxygen transfer particles increased, the fuel conversion rate and CO ₂ selectivity tended to increase.

Consequently, when methane, the main component of natural gas, is used as a fuel, it is advantageous to operate the chemical roofing system at a high temperature of ^{850 o} C or higher in order to improve the _{fuel conversion rate and CO 2 selectivity.}

On the other hand, in general, oxygen transfer particles are injected into the system in a state in which the metal component is oxidized (NiO state as in Equation (4) in the case of nickel-based oxygen transfer particles), and the reduction reaction proceeds by the fuel injected into the fuel reactor. The conversion of the particles is changed.

_{3 shows various fuels ((a)H 2} , (b)CH ₄ , (c) Syngas, (d) natural gas in the nickel-based oxygen transfer particles in the fuel reactor of the chemical roofing combustion system. ) shows a graph of the solid conversion rate over time when reacted.

That is, FIG. 3 shows the change in the conversion rate of oxygen-transferring particles measured with time change when hydrogen, methane, synthesis gas (CO, H ₂ are the main components), and natural gas were used as fuels (source: Ho-Jung Ryu) , Kyung-Su Kim, Yrong-Seong Park, Moon-Hee Park, “Reduction Characteristics pf Oxygen Carrier Particles for Chemical Looping Combustor with Different Fuels”, Trans. of the Korean Hydrogen and New Energy Society, Vol. 20, No. 1 , pp. 45-54 (2009)).

As shown in FIG. 3 , when fuel is injected into oxygen-transmitting particles in a completely oxidized state, the conversion rate of the particles increases as oxygen contained in the oxygen-transmitting particles reacts with the fuel, and when all the oxygen contained in the particles is consumed The conversion rate can be increased to 1.

In addition, as shown in (b) (d) of FIG. 3 , in the case _{of fuels (methane and natural gas) containing CH 4} , the conversion rate increases and then decreases again, which is not a decrease in the conversion rate but carbon deposition (carbon deposition). ), when the oxygen provided from the oxygen transfer particles is insufficient compared to the injected fuel (which occurs mainly when the conversion rate is high), carbon is added to the oxygen transfer particles through the reactions shown in Equations (5) and (6) below. It indicates the phenomenon of immersion.

CH ₄ → C + 2H ₂ (5)

2CO → C + CO ₂ (6)

When carbon is deposited on the oxygen transfer particles, the reactivity between the oxygen transfer particles and the gaseous fuel rapidly decreases, so it is advantageous to operate under conditions that can minimize carbon deposition.

On the other hand, the slope of the change in the solid conversion rate with time in FIG. 3 means the reaction rate, and as shown in FIG. 3, the rate of increase in the conversion rate is low at the beginning of the reaction, whereas at the conversion rate of 0.2 or more, the conversion rate rapidly increases with time change, and then the conversion Under this high condition, the increase slope tends to slow down.

As a result, the slope of the change in conversion rate with time, that is, the reaction rate, is higher under the condition of 0.4 ~ 0.6 conversion than the condition of low solid conversion, and carbon deposition may occur depending on the fuel under the condition of high conversion.

4 is a block diagram of a chemical roofing combustion system. Since the air reactor 10 plays a role of causing a reaction between oxygen transfer particles and air, and also plays a role of shooting the particles upward and transferring them to the fuel reactor 40 , a high-speed fluidized bed type is generally used.

The particles scattered from the air reactor 10 are transferred to the fuel reactor 40 through the air reactor cyclone 20 and the loop seal 30, and after reacting with the solid fuel in the fuel reactor 40, It is recirculated to the air reactor (10).

Since the oxygen transfer particles 1 repeat the oxidation-reduction reaction while continuously circulating between the air reactor 10 and the fuel reactor 40, the conversion rate of the solid particles shown in FIG. 3 ranges from 0 to 1. In the fuel reactor 40, since it reacts with the fuel, it shows a high conversion rate, and since it is oxidized again in the air reactor 10, it is changed to a low conversion rate.

Republic of Korea Patent Registration 10-1349493 Republic of Korea Patent Publication 10-2012-0045769 Republic of Korea Patent Publication 10-2018-0013283 Republic of Korea Patent Registration 10-0636881

As described above, it is advantageous to operate a chemical roofing combustion system using natural gas or methane as a fuel at a ^{temperature of 850 o} C or higher to obtain a _{high fuel conversion rate and CO 2 selectivity.} In the up process, it is necessary to preheat the temperature of the air reactor and the fuel reactor to 850°C or higher.

In the preheating process, indirect preheating by injecting high-temperature air or nitrogen is mainly used for preheating the reactor in order to prevent sintering due to a decrease in the reactivity of oxygen transfer particles due to a flame or a local high temperature generation.

This indirect preheating method has a low heat capacity of the injected high-temperature air or nitrogen, and heat loss may occur during the injection process, so it is difficult to directly transfer heat to the reactor or oxygen transfer particles present in the reactor. Therefore, a lot of time and energy are required in the preheating process of the chemical roofing combustion system.

In addition, in the case of a reduction reaction in a chemical looping combustion system, since it is an endothermic reaction, it is common not to inject fuel into the fuel reactor in the process of raising the temperature. In this case, the oxygen transfer particles are in a completely oxidized state (that is, the solid conversion rate is 0 in the state of being).

Therefore, when the desired temperature condition is reached, the reaction starts under the condition that the conversion rate of the solid particles is 0 under the conditions of circulating the solid and injecting fuel. Therefore, as shown in FIG. 3 , there is a disadvantage in that the reaction starts in a section with a low reaction rate, that is, the slope of the conversion rate change with time.

In addition, since the oxygen transfer particles continuously circulate between the air reactor and the fuel reactor, the oxygen transfer particles do not change repeatedly between a completely reduced state (solid conversion rate 1) and a fully oxidized state (solid conversion rate 0), but at a solid conversion rate of 0. It will cycle with any value between 1 (eg, the solid conversion varies between 0.0 and 0.3).

In this case, when the reaction starts in a state in which the oxygen transfer particles are completely oxidized, the conversion rate is changed under a low reaction rate condition (near conversion rate 0), and in this case, the performance of the entire system is deteriorated.

On the other hand, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned are clearly to those of ordinary skill in the art to which the present invention belongs from the description below. can be understood

A first object of the present invention is to provide a chemical roofing combustion system, comprising: an air reactor in which oxygen transfer particles are oxidized by reacting with air supplied by an air supply means; a fuel reactor in which oxygen transfer particles oxidized in the air reactor are supplied, fuel supplied by a fuel supply means is reacted to reduce the oxidized oxygen transfer particles, and the reduced oxygen transfer particles are supplied to the air reactor; an air reactor preheating means for preheating each of the air reactor and the fuel reactor to a preset temperature before driving the combustion system, and a fuel reactor preheating means; hydrogen supply means for supplying hydrogen gas into the fuel reactor before driving the combustion system; and controlling the air reactor preheating means and the fuel reactor preheating means so that the air reactor and the fuel reactor reach a set temperature, and the hydrogen supply means so that the solid conversion rate of the oxygen transfer particles in the fuel reactor reaches a set conversion rate value. It can be achieved as a chemical looping combustion system with improved reaction rate, comprising: a control unit to control

In addition, the air reactor preheating means and the fuel reactor preheating means may be characterized in that the indirect heating method for supplying the preheated gas is applied.

In addition, the air reactor and the fuel reactor are configured as a fluidized bed reactor, and include a first temperature sensor for measuring the temperature of the air reactor in real time, and a second temperature sensor for measuring the temperature of the fuel reactor in real time. can do.

And when the temperature of the fuel reactor reaches a first set temperature value, the control unit supplies nitrogen as a preheating gas, and causes hydrogen to be supplied to the fuel reactor through the hydrogen supply means to supply oxidized oxygen in the fuel reactor It may be characterized by controlling the transfer particles to be partially reduced.

In addition, the maximum amount of hydrogen supplied by the hydrogen supply means is the condition that the temperature of the fuel reactor does not decrease due to endotherm in the reaction process of hydrogen of the oxygen transfer particles, and the condition that hydrogen is not detected in the fuel reactor exhaust gas It may be characterized in that it is determined to satisfy

and a conversion rate calculator that calculates in real time the solid conversion rate of the oxygen transfer particles based on the hydrogen concentration injected into the fuel reactor and the discharged hydrogen concentration, and the mass and composition of the oxygen transfer particles charged into the fuel reactor, wherein the control unit calculates the conversion rate Controlled so that hydrogen is supplied by the hydrogen supply means until the solid conversion rate reaches the set conversion rate value based on the value calculated in part, and the air so that the fuel reactor and the air reactor reach a second set temperature value. It may be characterized in that the reactor preheating means and the fuel reactor preheating means are controlled.

In addition, it may be characterized in that it further comprises a flow rate control unit for adjusting the flow rate and the solid circulation rate of the air reactor.

And the control unit, the difference between the solid conversion rate in the fuel reactor and the solid conversion rate in the air reactor to maintain a set difference value, it may be characterized in that it controls the flow rate control unit.

In addition, the first set temperature value is 550 ~ 650 ℃, the second set temperature value is 800 ~ 900 ℃, the set conversion rate value is 0.4 ~ 0.6, it may be characterized in that the set difference value is 0.3 ~ 0.5.

and an air reactor cyclone provided at the discharge part of the air reactor to separate the oxygen transfer particles discharged from the air reactor from gas and supply them to the inlet side of the fuel reactor; and a loop seal provided between the air reactor cyclone and the fuel reactor.

In addition, the fuel reactor cyclone is provided at the discharge part of the fuel reactor to separate the oxygen delivery particles discharged from the fuel reactor from gas and recirculate to the fuel reactor side; it may further include a cyclone.

A second object of the present invention is a method for driving a chemical roofing combustion system according to the first object, comprising: a first step of charging oxidized oxygen transfer particles into a fuel reactor; a second step in which the controller preheats the air reactor through the air reactor preheating means and preheats the fuel reactor through the fuel reactor preheating means; a third step of supplying hydrogen into the fuel reactor by a control unit driving a hydrogen supply means when the fuel reactor and the air reactor reach a first set temperature value; a fourth step in which the oxygen transfer particles in the fuel reactor are partially reduced; When the solid conversion rate in the fuel reactor reaches a set conversion rate value, and the temperatures of the fuel reactor and the air reactor reach a second set temperature value, the control unit stops the hydrogen supply by the hydrogen supply means and turns off the fuel supply means. a fifth step of supplying fuel into the fuel reactor through the a sixth step in which the fuel supplied by the fuel supply means is reacted to reduce the oxygen transfer particles; a seventh step in which the reduced oxygen transfer particles are supplied to the air reactor, and the oxygen transfer particles are oxidized by reacting with the air supplied by the air supply means; and an eighth step in which the oxidized oxygen transfer particles are supplied to the fuel reactor and circulated.

And in the fifth step, the control unit is the hydrogen supply means and the air reactor preheating means so that the solid conversion rate in the fuel reactor reaches a set conversion rate value, and the temperatures of the fuel reactor and the air reactor reach a second set temperature value. and controlling the fuel reactor preheating means.

Also, in the third step, the maximum amount of hydrogen supplied by the hydrogen supply means is determined under the condition that the temperature of the fuel reactor does not decrease due to endothermic heat in the reaction process of hydrogen by oxygen transfer particles, and in the fuel reactor exhaust gas. It may be characterized in that it is determined to satisfy a condition in which hydrogen is not detected.

And in the sixth to eighth steps, the control unit may control the flow rate control unit so that the difference value between the solid conversion rate in the fuel reactor and the solid conversion rate in the air reactor is maintained such that a set difference value is maintained. have.

When the particles in a completely oxidized state are circulated, they do not react with oxygen in the air reactor, but according to the method for improving the reaction rate of the chemical roofing combustion system and the driving method using the same according to the embodiment of the present invention, the partially reduced particles By circulating, the temperature of the particles itself rises because they react with oxygen in the air reactor to generate heat, and have the effect of increasing the temperature of the air reactor and the particles faster and more effectively than the indirect heating type.

In addition, in the case of the conventional method, compared to starting the reaction in a section with a low reaction rate, according to the method for improving the reaction rate of the chemical roofing combustion system and the driving method using the same according to an embodiment of the present invention, the reaction is performed in the section with a high reaction rate. Since it can be operated in a high conversion rate range with a high reaction rate through control of the air flow rate and solid circulation rate injected into the air reactor, there is an advantage in that the reactivity in the fuel reactor is also improved.

On the other hand, the effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be able

The following drawings attached to this specification illustrate a preferred embodiment of the present invention, and serve to further understand the technical spirit of the present invention together with the detailed description of the present invention, so the present invention is limited to the matters described in those drawings It should not be construed as being limited.
1 is a conceptual diagram of a chemical roofing combustion system;
Figure 2a is a graph of the fuel conversion rate according to the reduction reaction temperature of the oxygen transfer particles for each of the three particles in the fuel reactor of the chemical roofing combustion system;
_{Figure 2b is a CO 2} selectivity graph according to the reduction reaction temperature of the oxygen transfer particles for each of the three particles in the fuel reactor of the chemical roofing combustion system;
_{3 shows various fuels ((a)H 2} , (b)CH ₄ , (c) Syngas, (d) natural gas in the nickel-based oxygen transfer particles in the fuel reactor of the chemical roofing combustion system. ) when reacted, the graph of the solid conversion rate according to time,
4 is a configuration diagram of a chemical roofing combustion system;
5 is a flowchart of a driving method of a chemical roofing combustion system with improved reaction speed according to an embodiment of the present invention;
6 is a block diagram showing a signal flow according to a control unit of a chemical looping combustion system with improved reaction speed according to an embodiment of the present invention;
7 is a graph showing a comparison of the range of change in the solid conversion rate by the conventional driving method and the driving method according to the present invention.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In this specification, when a component is referred to as being on another component, it may be directly formed on the other component or a third component may be interposed therebetween. In addition, in the drawings, the thickness of the components is exaggerated for the effective description of the technical content.

Embodiments described herein will be described with reference to cross-sectional and/or plan views, which are ideal illustrative views of the present invention. In the drawings, thicknesses of films and regions are exaggerated for effective description of technical content. Accordingly, the shape of the illustrative drawing may be modified due to manufacturing technology and/or tolerance. Accordingly, embodiments of the present invention are not limited to the specific form shown, but also include changes in the form generated according to the manufacturing process. For example, the region shown at right angles may be rounded or have a predetermined curvature. Accordingly, the regions illustrated in the drawings have properties, and the shapes of the regions illustrated in the drawings are intended to illustrate a particular shape of the region of the device and not to limit the scope of the invention. In various embodiments of the present specification, terms such as first, second, etc. are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another. The embodiments described and illustrated herein also include complementary embodiments thereof.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, the terms 'comprises' and/or 'comprising' do not exclude the presence or addition of one or more other components.

In describing the specific embodiments below, various specific contents have been prepared to more specifically describe the invention and help understanding. However, a reader having enough knowledge in this field to understand the present invention may recognize that it may be used without these various specific details. In some cases, it is mentioned in advance that parts that are commonly known and not largely related to the invention are not described in order to avoid confusion without any reason in describing the present invention in describing the invention.

Hereinafter, the configuration, function and driving method of the chemical roofing combustion system with improved reaction speed according to an embodiment of the present invention will be described.

First, FIG. 5 is a flowchart illustrating a method of driving a chemical roofing combustion system with improved reaction speed according to an embodiment of the present invention. And FIG. 6 is a block diagram showing a signal flow according to the control unit 60 of the chemical looping combustion system with improved reaction speed according to an embodiment of the present invention.

As shown in FIG. 4, the chemical roofing combustion system with improved reaction speed according to an embodiment of the present invention includes an air reactor, an air reactor cyclone 20, a loop seal 30, which are components of a conventional chemical roofing combustion system, It is configured to include a fuel reactor 40 , a fuel reactor cyclone 50 , and the like.

The air reactor 10 is configured to react with the air supplied by the air supply means 11 to oxidize the oxygen transfer particles. It has the form of a high-speed fluidized bed, and has a discharge part 12 on the upper side.

The oxidized oxygen transfer particles and gas discharged through the discharge unit 12 are separated through the air reactor cyclone 20 , and the solid oxygen transfer particles are supplied to the fuel reactor 40 through the loop seal 30 .

In the fuel reactor 40, the oxygen transfer particles oxidized in the air reactor 10 are supplied through the inlet pipe 42, and the fuel supplied by the fuel supply means 41 is reacted to reduce the oxidized oxygen transfer particles. , the reduced oxygen transfer particles are supplied to the air reactor 10 through the connection pipe 43 .

In addition, the gas discharged from the fuel reactor 40 and the scattered solids are introduced into the fuel reactor cyclone 50, and the gas discharged through the gas discharge unit 53 is then condensed with moisture to collect carbon dioxide, and the solid is discharged. The oxygen transfer particles discharged through the unit 52 are re-supplied to the fuel reactor 40 through the recirculation pipe 49 .

In addition, the chemical roofing combustion system with improved reaction speed according to an embodiment of the present invention includes an air reactor preheating means 14 for preheating each of the air reactor 10 and the fuel reactor 40 to a set temperature before driving, and the fuel It is configured to include a reactor preheating means (45).

The air reactor preheating means 14 and the fuel reactor preheating means 45 are applied with an indirect heating method for supplying preheated gas.

And the chemical looping combustion system with improved reaction speed according to an embodiment of the present invention is configured to include a hydrogen supply means 48 for supplying hydrogen gas into the fuel reactor 40 before driving.

The control unit 60 controls the air reactor preheating means 14 and the fuel reactor preheating means 45 so that the air reactor 10 and the fuel reactor 40 reach a set temperature before the combustion system is driven, and the fuel reactor ( 40), the hydrogen supply means 48 is controlled so that the solid conversion rate of the oxygen transfer particles in the compound reaches a set conversion rate value.

And it is configured to measure the temperature of the air reactor 10 in real time through the first temperature sensor 13 and to measure the temperature of the fuel reactor 40 in real time by the second temperature sensor 46 .

When the temperature of the fuel reactor 40 reaches a first set temperature value, the control unit 60 supplies nitrogen as a preheating gas and simultaneously supplies hydrogen to the fuel reactor 40 through the hydrogen supply means 48 . Thus, it is controlled to partially reduce the oxidized oxygen transfer particles in the fuel reactor 40 . This first set temperature value corresponds to about 550 ~ 650 ℃ (for example, 600 ℃).

In addition, the maximum amount of hydrogen supplied by the hydrogen supply means 48 is a condition that the temperature of the fuel reactor 40 does not decrease due to endothermic heat in the reaction process between the oxygen transfer particles and hydrogen, and the fuel reactor 40 It is controlled to satisfy the condition that no hydrogen is detected in the exhaust gas.

And a conversion rate calculator 47 that calculates in real time the solid conversion rate of the oxygen transfer particles based on the hydrogen concentration injected into the fuel reactor 40 and the discharged hydrogen concentration, and the mass and composition of the oxygen transfer particles charged in the fuel reactor 40 . ), and the control unit 60 controls hydrogen to be supplied by the hydrogen supply means 48 until the solid conversion rate reaches a set conversion rate value based on the value calculated by the conversion rate calculation unit 47 . And the controller 60 controls the air reactor preheating means 14 and the fuel reactor preheating means 45 so that the fuel reactor 40 and the air reactor 10 reach the second set temperature value.

This second set temperature value is about 800 to 900 ° C (for example, 850 ° C), and the set conversion rate value is 0.4 to 0.6 (for example, 0.5).

In addition, it is configured to include a flow rate control unit 15 for adjusting the flow rate and the solid circulation rate of the air reactor (10). Therefore, the control unit 60 controls the flow rate control unit 15 so that the difference value (conversion rate range) in which the difference value between the solid conversion rate in the fuel reactor 40 and the solid conversion rate in the air reactor 10 is maintained is maintained. . This set difference value (conversion rate difference range) is about 0.3 to 0.5 (eg, 0.4).

That is, by controlling the flow rate and the solid circulation rate of the air reactor 10, it is possible to control the oxygen delivery particles not to be completely oxidized, and through this, even after the oxidized particles are moved to the fuel reactor 40, the reaction rate is high in the section. It is possible to control the reduction reaction to occur.

Hereinafter, a method of driving a chemical roofing combustion system with improved reaction speed will be described.

First, the oxidized oxygen transfer particles are charged only to the fuel reactor 40 (S1). In a state in which only the fuel reactor 40 is charged with oxygen transfer particles, the air reactor 10 and the fuel reactor 40 are heated by an indirect heating method (high-temperature air or nitrogen injection) through the preheating means 14 and 45. (S2).

Then, after heating to 600° C. (first set temperature value), which is a stable temperature at which oxygen transfer particles can be oxidized by reacting with air and reduced by fuel, the injected gas of the fuel reactor 40 is exchanged with nitrogen do.

And hydrogen is injected through the hydrogen supply means 48 together with the nitrogen injected into the fuel reactor 40 (S3) (However, if a gas containing a carbon component other than hydrogen is injected, carbon deposition may occur.) .

In addition, when nitrogen and hydrogen are injected together, since oxygen does not exist, combustion of hydrogen does not occur in the process of passing through the preheating means 45 such as a gas preheating heater and reaches the fuel reactor 40 and comes into contact with the oxygen transfer particles. At the bottom, it reacts with the oxygen contained in the oxygen transfer particles as shown in Equation (7) and is discharged in the form of water vapor.

NiO + H ₂ → Ni + H ₂ O (7)

In this process, the temperature increase effect by the preheated nitrogen and hydrogen and the temperature decrease effect by the reaction (endothermic reaction) between hydrogen and oxygen transfer particles work together.

As mentioned above, the maximum amount of hydrogen to be injected may be determined under the condition that the following two conditions are satisfied.

1) A condition in which the temperature of the fuel reactor 40 does not decrease due to the endothermic heat in the reaction process of oxygen transfer particles and hydrogen

2) A condition in which hydrogen is not detected in the exhaust gas of the fuel reactor 40

When the above conditions are satisfied, as the temperature of the fuel reactor 40 increases, the oxygen transfer particles inside the fuel reactor 40 are reduced, so the oxygen contained in the oxygen transfer particles decreases, and the conversion rate of the solid increases (S4). ).

In addition, the time for injecting hydrogen by the hydrogen supply means 48 can be controlled through the weight of the solid charged in the fuel reactor 40, and the gradient of the change in the solid conversion rate with time (that is, shown in FIG. 3 ) It can proceed to a section with a high reaction rate).

Preferably, in order to maintain a wide difference in the solid conversion rate between the air reactor 10 and the fuel reactor 40, up to a solid conversion rate of 0.5 (a set solid conversion rate value) is injected.

In addition, when the desired operation start temperature is reached, but the conversion rate of the oxygen transfer particles does not reach the desired level (the set solid conversion rate value), the temperature can be controlled by controlling the preheating means 14 and 45, and the desired operation start temperature If the (second set temperature value) is not reached, but the conversion rate of the oxygen transfer particles reaches a desired level, the hydrogen injection may be stopped and the temperature may be increased using only the preheating means 14 and 45 (S5).

And when the temperature of the system reaches the desired operation start temperature (the second set temperature value) and the conversion rate of oxygen transfer particles becomes a set conversion rate value (for example, 0.5), nitrogen and hydrogen injected into the fuel reactor 40 The particles are circulated to the air reactor 10 while being converted into fuel gas (eg, natural gas) (S6).

At this time, since the oxygen transfer particles are in a partially reduced state (that is, oxygen is consumed), they react with oxygen in the air in the air reactor 10 to react as shown in Equation (3), and since it is an exothermic reaction, the oxygen transfer particles themselves heat is generated in

Through this reaction, the temperature of the air reactor 10 can be increased additionally, and since the oxygen transfer particles themselves generate heat, it is faster and more effective than when the temperature is raised indirectly using high-temperature air, etc. (10) and the temperature of the oxygen transfer particles can be increased.

In the fuel reactor 40, the fuel gas reacts with the injected fuel gas, and since it reacts with the fuel in a region with a high reaction rate, it is possible to obtain a result with superior reactivity compared to a fully oxidized state (solid conversion rate 0).

In addition, by controlling the flow rate and the solid circulation rate of the air reactor 10, it is possible to control so that the oxygen transfer particles are not completely oxidized (that is, the solid conversion rate does not become 0), and through this, the oxidized particles are transferred to the fuel reactor 40 ), it is possible to control the reduction reaction to occur in a section with a high reaction rate even after moving to (S7).

7 is a graph showing a comparison of the range of change in the solid conversion rate by the conventional driving method and the driving method according to the present invention. As shown in FIG. 7 , a case in which the difference in the solid conversion rate between the air reactor 10 and the fuel reactor 40 is equal to 0.4 is compared.

In the case of the conventional operation method (Case 1), since the operation starts in a state in which the oxygen transfer particles are completely oxidized, the solid conversion rate is changed between 0.0 and 0.4, whereas according to the embodiment of the present invention, the average solid conversion rate is controlled under the condition of 0.5 Then, it becomes a condition to change the solid conversion rate between 0.3 and 0.7 (the difference in the solid conversion rate is the same 0.4).

When the oxygen transfer particles start to circulate and react in a completely oxidized state, the oxygen transfer particles have a low reaction rate (slope of change in conversion rate with time) (Case 1 of [Fig. 7]). In contrast to the conditions in which the reaction is started and maintained, according to the embodiment of the present invention, when the oxygen transfer particles are partially reduced using hydrogen and then circulation and reaction are started, the oxygen transfer particles are in a section with a high reaction rate (Case in FIG. 7 ). 2), the reaction can be maintained.

In the case of circulating particles in a completely oxidized state, while they do not react with oxygen in the air reactor 10, according to the method for improving the reaction rate of the chemical roofing combustion system and the driving method using the same according to the embodiment of the present invention, some reduction By circulating the particles, the temperature of the particles itself rises because they react with oxygen in the air reactor 10 to generate heat, and the temperature of the air reactor 10 and the particles can be raised more quickly and effectively compared to the indirect heating type. have an effect

In addition, in the case of the conventional method, compared to starting the reaction in a section with a low reaction rate, according to the method for improving the reaction rate of the chemical roofing combustion system according to an embodiment of the present invention and the driving method using the same, the reaction is performed in the section with a high reaction rate. Since it can be operated in a high conversion rate range with a high reaction rate through control of the air flow rate and solid circulation rate injected into the air reactor 10 , the reactivity in the fuel reactor 40 is also improved.

In addition, in the apparatus and method described above, the configuration and method of the above-described embodiments are not limitedly applicable, but all or part of each embodiment is selectively combined so that various modifications can be made to the embodiments. may be configured.

1: Oxygen transfer particles
10: air reactor
11: Air supply means
12: discharge part
13: first temperature sensor
14: air reactor preheating means
15: flow control unit
20: air reactor cyclone
21: air reactor cyclone inlet
22: air reactor cyclone solid discharge part
23: air reactor cyclone gas outlet
30: loop seal
40: fuel reactor
41: fuel supply means
42: inlet pipe
43: connector
44: discharge part
45: fuel reactor preheating means
46: second temperature sensor
47: conversion rate calculator
48: hydrogen supply means
49: recirculation tube
50: fuel reactor cyclone
51: fuel reactor cyclone inlet
52: fuel reactor cyclone solid discharge unit
53: fuel reactor cyclone gas discharge unit
60: control unit

Claims (15)

In the chemical roofing combustion system,
an air reactor in which oxygen transfer particles are oxidized by reacting with air supplied by the air supply means;
a fuel reactor in which oxygen transfer particles oxidized in the air reactor are supplied, fuel supplied by a fuel supply means is reacted to reduce the oxidized oxygen transfer particles, and the reduced oxygen transfer particles are supplied to the air reactor;
an air reactor preheating means for preheating each of the air reactor and the fuel reactor to a preset temperature before driving the combustion system, and a fuel reactor preheating means;
hydrogen supply means for supplying hydrogen gas into the fuel reactor before driving the combustion system; and
The air reactor preheating means and the fuel reactor preheating means are controlled so that the air reactor and the fuel reactor reach a set temperature, and the hydrogen supply means is controlled so that the solid conversion rate of the oxygen transfer particles in the fuel reactor reaches a set conversion rate value. A chemical roofing combustion system with an improved reaction rate, comprising: a control unit.
The method of claim 1,
The chemical roofing combustion system with improved reaction rate, characterized in that the air reactor preheating means and the fuel reactor preheating means are applied with an indirect heating method for supplying preheated gas.
3. The method of claim 2,
The air reactor and the fuel reactor are composed of a fluidized bed reactor,
A chemical looping combustion system with improved reaction speed, comprising: a first temperature sensor for measuring the temperature of the air reactor in real time; and a second temperature sensor for measuring the temperature of the fuel reactor in real time.
4. The method of claim 3,
When the temperature of the fuel reactor reaches a first set temperature value, the control unit supplies nitrogen as a preheating gas and supplies hydrogen to the fuel reactor through the hydrogen supply means to transfer oxidized oxygen in the fuel reactor A chemical roofing combustion system with an improved reaction rate, characterized in that it is controlled to partially reduce the particles.
5. The method of claim 4,
The maximum amount of hydrogen supplied by the hydrogen supply means is,
The reaction rate is improved, characterized in that it is determined to satisfy the condition that the temperature of the fuel reactor does not decrease due to the endothermic heat in the reaction process of hydrogen of the oxygen transfer particles and the condition that hydrogen is not detected in the fuel reactor exhaust gas Chemical roofing combustion system.
6. The method of claim 5,
Further comprising a conversion rate calculator that calculates in real time the solid conversion rate of the oxygen transfer particles based on the hydrogen concentration injected into the fuel reactor and the discharged hydrogen concentration, and the mass and composition of the oxygen transfer particles charged into the fuel reactor,
The control unit controls so that hydrogen is supplied by the hydrogen supply means until the solid conversion rate reaches the set conversion rate value based on the value calculated by the conversion rate calculation unit, and the fuel reactor and the air reactor have a second set temperature value A chemical roofing combustion system with improved reaction rate, characterized in that controlling the air reactor preheating means and the fuel reactor preheating means to reach
7. The method of claim 6,
Chemical roofing combustion system with improved reaction rate, characterized in that it further comprises a flow rate control unit for adjusting the flow rate and the solid circulation rate of the air reactor.
8. The method of claim 7,
The control unit is
A chemical looping combustion system with improved reaction rate, characterized in that the flow control unit is controlled so that the difference value between the solid conversion rate in the fuel reactor and the solid conversion rate in the air reactor is maintained so that the set difference value is maintained.
9. The method of claim 8,
The first set temperature value is 550 ~ 650 ℃,
The second set temperature value is 800 ~ 900 ℃,
The set conversion rate value is 0.4 to 0.6,
The set difference value is a chemical roofing combustion system with an improved reaction rate, characterized in that 0.3 to 0.5.
◈Claim 10 was abandoned when paying the registration fee.◈ 9. The method of claim 8,
an air reactor cyclone provided at the outlet of the air reactor to separate the oxygen transfer particles discharged from the air reactor from gas and supply to the inlet side of the fuel reactor; and
A chemical roofing combustion system with improved reaction speed, further comprising a loop seal provided between the air reactor cyclone and the fuel reactor.
◈Claim 11 was abandoned when paying the registration fee.◈ 11. The method of claim 10,
A chemical looping combustion system with improved reaction rate, characterized in that it further comprises; a fuel reactor cyclone provided at the discharge part of the fuel reactor to separate the oxygen delivery particles discharged from the fuel reactor from gas and recirculate them to the fuel reactor. .
In the driving method of the chemical roofing combustion system according to any one of claims 1 to 11,
A first step of loading the oxidized oxygen transfer particles into the fuel reactor;
a second step in which the controller preheats the air reactor through the air reactor preheating means and preheats the fuel reactor through the fuel reactor preheating means;
a third step of supplying hydrogen into the fuel reactor by a control unit driving a hydrogen supply means when the fuel reactor and the air reactor reach a first set temperature value;
a fourth step in which the oxygen transfer particles in the fuel reactor are partially reduced;
When the solid conversion rate in the fuel reactor reaches a set conversion rate value, and the temperatures of the fuel reactor and the air reactor reach a second set temperature value, the control unit stops the hydrogen supply by the hydrogen supply means and turns off the fuel supply means a fifth step of supplying fuel into the fuel reactor through the
a sixth step in which the fuel supplied by the fuel supply means is reacted to reduce the oxygen transfer particles;
a seventh step in which the reduced oxygen transfer particles are supplied to the air reactor and react with the air supplied by the air supply means to oxidize the oxygen transfer particles; and
and an eighth step in which the oxidized oxygen transfer particles are supplied to the fuel reactor and circulated.
◈Claim 13 was abandoned when paying the registration fee.◈ 13. The method of claim 12,
In the fifth step
The hydrogen supply means, the air reactor preheating means, and the fuel reactor preheating means so that the control unit reaches the conversion rate value set in the solid conversion rate in the fuel reactor, and the temperatures of the fuel reactor and the air reactor reach a second set temperature value A driving method of a chemical roofing combustion system, characterized in that controlling the.
◈Claim 14 was abandoned at the time of payment of the registration fee.◈ 14. The method of claim 13,
In the third step,
The maximum amount of hydrogen supplied by the hydrogen supply means is the condition that the temperature of the fuel reactor does not decrease due to endotherm in the reaction process of hydrogen of the oxygen transfer particles, and the condition that hydrogen is not detected in the fuel reactor exhaust gas. A driving method of a chemical roofing combustion system, characterized in that it is determined to be satisfied.
◈Claim 15 was abandoned when paying the registration fee.◈ 15. The method of claim 14,
In the sixth to eighth steps, the control unit controls the flow rate control unit so that the difference value between the solid conversion rate in the fuel reactor and the solid conversion rate in the air reactor is maintained such that a set difference value is maintained. How to drive the combustion system.

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