CN101216175A - Oxygen carrier oxidation combustion method and device thereof - Google Patents

Abstract

The invention discloses a method and device for oxygen-carrying oxidation combustion of an oxygen carrier. The method is that the oxygen carrier is placed in an air reactor fluidized bed, and fluidized air is passed through, and the oxygen body reacts with oxygen in the air to obtain a The heated high-valence metal oxide is then separated by a two-stage separator; the separated high-temperature oxygen-poor air is discharged from the upper end of the separator, and the separated oxygen carrier passes through the return leg and enters the mixed gasification chamber; In the circulating fluidized bed of the air reactor, the oxygen carrier reacts with the oxygen in the air: the oxygen carrier produced by the reaction enters the dipleg after being separated by the two-stage separator, and enters the fuel reactor together with the fuel The gasification chamber at the lower part of the fluidized bed. In the gasification chamber, fuel and water vapor undergo a gasification reaction to generate syngas. At the same time, the oxygen carrier releases oxygen, which undergoes reduction reaction with synthesis gas or fuel to generate carbon dioxide.

Description

Oxygen carrier oxidation combustion method and device thereof

technical field

The invention relates to a method and device for separating carbon dioxide during the combustion process by using an oxygen carrier to carry out a process similar to steam gasification and pure oxygen combustion of coal/natural coke/petroleum coke, especially to an oxygen carrier Oxygen-carrying oxidation combustion method and device thereof.

Background technique

One of the sustainable development strategies of energy utilization is to realize the efficient and clean utilization of energy. Coal, natural coke and petroleum coke are used as energy sources. During the combustion process, reducing carbon dioxide emissions and realizing efficient and clean utilization is the future development direction. Conventional air direct combustion, in addition to the formation of nitrogen oxides, consumes a lot of energy to remove carbon dioxide from the flue gas; the method of carbon dioxide separation and combustion through coal gasification also requires energy consumption for oxygen production and carbon dioxide separation. If this method is used for power generation, the energy consumed can account for more than 10% of the power consumption rate of the factory, which seriously affects the energy utilization efficiency.

Contents of the invention

The present invention provides an oxygen-carrier oxygen-carrying oxidative combustion method capable of separating and obtaining carbon dioxide and its device. The present invention can effectively separate carbon dioxide while performing energy conversion on coal/natural coke/petroleum coke, and does not need to consume additional energy consumption. And it is beneficial to the advantages of environmental protection.

Method technical scheme of the present invention is as follows:

An oxygen-carrier oxygen-carrying oxidation combustion method, the low-valence metal oxide or metal element as the oxygen carrier is placed in the fluidized bed of the air reactor, and fluidized air is introduced from the lower end of the fluidized bed of the air reactor, Low-valence metal oxides or metal elemental oxygen carriers react with oxygen in the air to obtain heated high-valence metal oxides, which are then separated by a two-stage separator; the separated high-temperature oxygen-deficient air passes through the The upper end is discharged, and the separated oxygen carrier passes through the return leg and enters the lower mixed gasification chamber of the fluidized bed of the fuel reactor; the lower end of the fluidized bed of the fuel reactor is passed into the gasification medium steam, , the oxygen carrier provides the heat for the gasification of coal, natural coke or petroleum coke and water vapor, and the gasified synthesis gas undergoes a reduction reaction with the oxygen carrier to reduce the high-valence metal oxide to the low-valence metal oxide The substance or metal element reacts fully in the upper riser of the fluidized bed of the fuel reactor, and then enters the separator, and the separated clean carbon dioxide and water vapor mixture is discharged from the upper end of the separator, and pure carbon dioxide is obtained after condensing water; the separated The mixed solid matter of oxygen carrier and carbon residue enters the air reactor fluidized bed through the oxygen carrier circulation material leg, and the oxygen carrier is regenerated to realize oxygen carrying.

Device technical scheme of the present invention is as follows:

A device for implementing the oxygen-carrier method described in claim 1, comprising an air reactor fluidized bed, an oxygen-carrying heat-carrying return pipe, an oxygen-carrier regeneration separator, an oxygen-carrier regeneration return pipe, and a fuel reaction The upper end of the fluidized bed of the air reactor is connected with an oxygen-deficient air separator, and the discharge port at the lower end of the oxygen-deficient air separator is connected with one end of the oxygen-carrying heat-carrying return pipe, and the oxygen-carrying heat-carrying return pipe The other end of the fuel reactor fluidized bed is connected to the lower end, the upper end of the fuel reactor fluidized bed is connected to the upper end of the oxygen carrier regeneration separator, and the lower end of the oxygen carrier regeneration separator is connected to one end of the oxygen carrier regeneration return pipe. The other end of the oxygen carrier regeneration return pipe is connected to the lower part of the fluidized bed of the air reactor.

Compared with prior art, the present invention has following advantage:

(1) In the circulating fluidized bed of the air reactor, the oxygen carrier (such as: low-valent iron oxide, nickel, copper, zinc, etc.) reacts with the oxygen in the air:

2Ni+O ₂ →2NiO+exothermic

2Fe _x O _y + O ₂ → 2Fe _x O _{y + 1} + exotherm

2Cu+O ₂ →2CuO+exothermic

2Zn+O ₂ →2ZnO+exothermic

The oxygen carrier generated by the reaction (such as: high-valent iron oxide, nickel oxide, copper oxide, zinc oxide, etc.), after being separated by the two-stage separator, enters the dipleg, and together with the fuel, enters the lower part of the fluidized bed of the fuel reactor. In the gasification chamber, fuel and water vapor undergo a gasification reaction to generate syngas. At the same time, the oxygen carrier (simplified as M _x O _y ) releases oxygen, which undergoes a reduction reaction with syngas or fuel to generate carbon dioxide:

H ₂ O+C→4H ₂ +CO+ endothermic

Me _x O _y+1 +CO→CO ₂ +Me _x O _y + endothermic

Me _x O _y+1 +H ₂ →H ₂ O+Me _x O _y + endothermic

2Me _x O _y+1 +C→CO ₂ +2Me _x O _y + endothermic

The generated flue gas passes through two sets of cyclone separators to discharge the flue gas. After energy recovery and condensation, the flue gas becomes pure carbon dioxide. The separator separates the separated solid material into two streams. One of the solid materials enters the fluidized bed of the air reactor through the material leg, and undergoes an oxidation regeneration reaction to complete the oxygen-carrying regeneration process; the other enters the fluidized bed of the fuel reactor for gasification and reduction reactions to increase the conversion rate of carbon .

(2) The present invention has adopted two groups of flue gas separators, can separate the solid material of the fuel reactor fluidized bed separator into two strands, and by connecting pipelines, the solid material is sent into the air reactor fluidized bed and the air reactor fluidized bed respectively Fuel Reactor Fluidized Bed. The operating temperature of the fluidized bed of the air reactor can be controlled at about 800 ° C ~ 1250 ° C, and the remaining heat can be controlled by laying the heating surface or increasing the air flow; the temperature of the mixed gasification chamber at the lower part of the fluidized bed of the fuel reactor is controlled at 800 ° C ~ Around 1200°C, the temperature of the upper riser can be slightly lower in the range of 500°C to 900°C.

(3) The present invention uses metal oxides as oxygen carriers to carry out gasification and combustion with water vapor, coal/natural coke/petroleum coke at a temperature of 900°C to 1250°C, which has the same advantages as using pure oxygen combustion. Flue gas composition (that is, to obtain flue gas containing only carbon dioxide and water vapor), but there is no need for the energy consumption of producing pure oxygen (usually for power generation, the energy consumption of oxygen production accounts for more than 10% of the power consumption of the plant), and there is no NOx Generation, and the external emissions during the energy conversion process can be effectively controlled.

Description of drawings

Fig. 1 is a structural schematic diagram of an embodiment of the present invention, in which H is an oxygen-poor air outlet, I1 and I2 are carbon dioxide water vapor outlets, B is a supplementary oxygen carrier inlet, and F is a fuel inlet.

Fig. 2 is an utilization scheme of the embodiment of the present invention.

Detailed ways

Example 1

An oxygen-carrying oxygen-carrying oxidation combustion method, the low-valence metal oxide or metal element as the oxygen carrier is placed in the fluidized bed of the _air reactor, and the metal oxide as the oxygen carrier is _Fe2O3 , FeO, Fe ₃ O ₄ , CuO, Cu ₂ O, NiO, and ZnO, and the metal element as the oxygen carrier is Fe, Cu, Zn, and Ni. Then, the fluidized air is introduced from the lower end C of the fluidized bed of the air reactor, and the low-valence metal oxide or metal elemental oxygen carrier reacts with the oxygen in the air to obtain the heated high-valence metal oxide, and then make it pass through two Stage separator separation; the separated high-temperature oxygen-depleted air is discharged from the upper end H of the separator, and the separated oxygen carrier passes through the return leg and enters the lower mixed gasification chamber of the fuel reactor fluidized bed; the fuel reactor flow The lower end E of the gasification bed is fed with gasification medium steam. In the mixed gasification chamber, the oxygen carrier provides the heat for the gasification of coal, natural coke or petroleum coke and water vapor. The gasified synthesis gas and the oxygen carrier generate Reduction reaction, reducing high-valence metal oxides to low-valence metal oxides or simple metals, fully reacting in the upper riser of the fluidized bed of the fuel reactor, and then entering the separator, the separated clean carbon dioxide and water vapor mixture It is discharged from the upper end I1 of the separator, and pure carbon dioxide is obtained after condensing the water; the separated oxygen carrier and carbon residue mixed solid matter enters the fluidized bed of the air reactor through the oxygen carrier circulation material leg 4, and the oxygen carrier is regenerated to realize Oxygen.

High-valence metal oxides are reduced to low-valence metal oxides or simple metals. After fully reacting in the upper riser of the fluidized bed of the fuel reactor, part of them enters another separator. The separated clean carbon dioxide and water-steam mixture is released from The upper end I2 of the separator is discharged, and the oxygen carrier and carbon residue mixed solids separated by the separator pass through the carbon residue circulation dipleg 5-4, and then return to the gasification reaction chamber at the lower part of the fluidized bed of the fuel reactor to improve Carbon burnout rate.

Further detailed description is given below: the low-valence metal oxide or metal element as the oxygen carrier is placed in the fluidized bed of the air reactor, and the fluidized air is introduced from the lower part of the fluidized bed of the air reactor, and the air reactor flows The operating temperature of the chemical bed can be controlled at about 800°C to 1250°C. At this time, the low-valence metal oxide or metal elemental oxygen carrier reacts with the oxygen in the air to obtain a high-valence metal oxide, and then passes through the two-stage separator , the separated high-temperature clean oxygen-depleted air can be used for power generation or waste heat utilization; the separated oxygen carrier, through the return leg, enters the lower mixed gasification chamber of the fluidized bed of the fuel reactor, and the high-temperature oxygen carrier provides coal/natural The heat of gasification of coke/petroleum coke and water vapor, the temperature of the mixed gasification chamber is controlled at about 800 ℃ ~ 1200 ℃; at this time, coal/natural coke/petroleum coke and water vapor undergo gasification reaction, and the gasified The reduction reaction with the oxygen carrier can occur in the gasification chamber, and the metal oxide in the high-valence state can be reduced to the metal oxide in the low-valence state or the metal element, which can fully react in the riser of the fluidized bed, and the temperature of the riser can be slightly lower at 500 ℃ ~ 900 ℃; after that, the flue gas enters two sets of two-stage separators, and the separated clean carbon dioxide and water vapor mixture is condensed to obtain pure carbon dioxide after power generation or waste heat utilization; one of them is separated The oxygen carrier (containing unreacted carbon residue) passes through the material leg, and then returns to the gasification reaction chamber at the lower part of the fluidized bed of the fuel reactor to increase the carbon burn-out rate; the other group of separated oxygen carriers passes through the material The legs enter the fluidized bed of the air reactor to regenerate the oxygen carrier to realize oxygen carrying. The reaction product in the fuel reactor fluidized bed is a low-valence metal oxide or metal element, and the low-valence metal oxide or metal element oxygen carrier is divided into two streams through two sets of fuel reactor fluidized bed separators. One of the reduced oxygen carriers (containing unreacted residual carbon) returns to the gasification chamber at the lower part of the fluidized bed of the fuel reactor through the material leg to further increase the conversion rate of carbon and increase the burnout rate; The oxygen carrier (containing unreacted residual carbon) enters the air reactor fluidized bed through the material leg, oxidizes the reduced oxygen carrier to the oxidized oxygen carrier, and raises the temperature, and passes through the air reactor fluidized bed separator , and then enter the gasification chamber at the lower part of the fluidized bed of the fuel reactor as an oxygen-carrying heat carrier.

Example

A device for implementing the oxygen carrier method, comprising an air reactor fluidized bed 1, an oxygen-carrying heat-carrying return pipe 2, an oxygen carrier regeneration separator 3, an oxygen carrier regeneration return pipe 4 and a fuel Reactor fluidized bed 5 is composed of, the upper end of air reactor fluidized bed 1 is connected with oxygen-deficient air separator 1-1, and the lower end discharge port of oxygen-deficient air separator 1-1 is connected with oxygen-carrying heat-carrying return pipe 2. One end is connected, the other end of the oxygen-carrying heat-carrying return pipe 2 is connected with the lower end of the fuel reactor fluidized bed 5, and the upper end of the fuel reactor fluidized bed 5 is connected with the upper end of the oxygen carrier regeneration separator 3, and the oxygen carrier The lower end of the regeneration separator 3 is connected with one end of the oxygen carrier regeneration return pipe 4 , and the other end of the oxygen carrier regeneration return pipe 4 is connected with the lower part of the air reactor fluidized bed 1 . An oxygen carrier supplement port B is provided at the lower end of the circulating fluidized bed 1 of the air reactor. The fuel reactor circulating fluidized bed 5 is composed of a riser type, a mixed gasification reaction chamber 5-3 and a transition section 5-2, and the riser type is connected with the mixed gasification reaction chamber 5-3 through the transition section 5-2. The upper outlet of the first-stage oxygen-poor air separator 1-1 is connected with a second-stage oxygen-poor air separator 1-2, and the upper end of the second-stage oxygen-poor air separator 1-2 is provided with an oxygen-poor air outlet H, and the first-stage oxygen-poor air separator The lower end of the device 1-1 is connected with the oxygen carrier return leg 1-3, the lower part of the secondary oxygen-poor air separator 1-2 communicates with the oxygen carrier return leg 1-3, and the oxygen carrier return leg 1-3 The lower end of the moving bed is connected with a moving bed 1-4, the lower end of the moving bed 1-4 is provided with a fluidization air inlet A, and the lower part of the moving bed 1-4 is provided with a material outlet and the material outlet is used as the lower end of the oxygen-poor air separator 1-1 The discharge port is used. The upper end of the fuel reactor fluidized bed 5 is also connected with a carbon residue separator, which is composed of a primary flue gas carbon residue separator 5-1 and a secondary flue gas carbon residue separator 5-5. The lower end of the flue gas carbon residue separator 5-1 is connected with a carbon residue return leg 5-6, and the carbon residue return leg 5-6 communicates with the outlet of the secondary flue gas residue carbon separator 5-5, and the carbon residue return leg 5 The lower end of -6 is connected with the moving bed 5-7, the lower end of the moving bed 5-7 is provided with a fluidized air inlet G, and the lower part of the moving bed 5-7 is provided with a material outlet, which is connected to the reactor fluidized bed through the circulating return pipe 5-4 The bottom of 5 is connected. Oxygen carrier regeneration separator 3 is composed of primary flue gas oxygen carrier regeneration separator 3-1 and secondary flue gas oxygen carrier regeneration separator 3-2, primary flue gas oxygen carrier regeneration separator 3-1 It communicates with the outlet of the secondary flue gas oxygen carrier regeneration separator 3-2, and the outlet of the primary flue gas oxygen carrier regeneration separator 3-1 is connected with the oxygen carrier regeneration return leg, and the oxygen carrier regeneration return leg 3 The lower end of the moving bed is connected with a moving bed 3-3, the lower end of the moving bed 3-3 is provided with a fluidization air inlet D, and the lower part of the moving bed 3-3 is provided with a material outlet and the material outlet is connected to one end of the oxygen carrier regeneration return pipe 4 .

Example 3

A method for realizing carbon dioxide separation during coal/natural coke/petroleum coke combustion by utilizing the present invention, that is, using coal/natural coke/petroleum coke for clean power generation and simultaneously realizing the separation of carbon dioxide. Referring to Fig. 2, after the air is compressed by the compressor 8, it becomes high-pressure air, enters the fluidized bed of the air reactor of Example 1, and reacts with the reduced oxygen carrier to obtain high-temperature, high-pressure, oxygen-poor air and carries oxygen through the air reactor The body separator is separated, and the high-pressure oxygen-poor air enters the turbine 7 to expand and do work, driving the generator 6 to generate electricity, and the exhaust gas from the turbine 7 enters the waste heat recovery power generation system 9 to generate electricity or steam. The oxygen carrier separated by the oxygen carrier separator of the air reactor enters the fluidized bed of the fuel reactor, and is gasified and combusted with the steam E and coal/natural coke/petroleum coke F generated by the waste heat recovery power generation system 9 or 12 to generate high temperature The flue gas and high-temperature flue gas need to be separated by two sets of fuel reactor separators. The flue gas is expanded through the turbine 10 to do work, drives the generator 11 to generate electricity, and the exhaust gas from the turbine 10 enters the waste heat recovery power generation system 12 to generate electricity or steam. The tail gas K of the recovery power generation system 12 is condensed into pure carbon dioxide. The oxygen carrier separated by the fuel reactor separator is divided into two streams, one stream returns to the fluidized bed of the fuel reactor to participate in gasification and combustion reactions, and the other stream enters the fluidized bed of the air reactor to carry oxygen .

Claims (9)

1. An oxygen-carrier oxygen-carrying oxidative combustion method is characterized in that the low-valence metal oxide or metal elemental substance as the oxygen carrier is placed in the air reactor fluidized bed, from the lower end of the air reactor fluidized bed (C) Fluidizing air is introduced, and the low-valence metal oxide or metal elemental oxygen carrier reacts with the oxygen in the air to obtain the heated high-valence metal oxide, which is then separated by a two-stage separator; the separated The high-temperature oxygen-depleted air is discharged from the upper end (H) of the separator, and the separated oxygen carrier passes through the return leg and enters the lower mixed gasification chamber of the fluidized bed of the fuel reactor; the lower end (E) of the fluidized bed of the fuel reactor ) into the gasification medium steam, in the mixed gasification chamber, the oxygen carrier provides the heat for the gasification of coal, natural coke or petroleum coke and water vapor, and the gasified synthesis gas undergoes a reduction reaction with the oxygen carrier, and the High-valence metal oxides are reduced to low-valence metal oxides or simple metals, fully reacted in the upper riser of the fluidized bed of the fuel reactor, and then enter the separator, and the separated clean carbon dioxide and water-steam mixture is discharged from the separator The upper end (I1) is discharged, and pure carbon dioxide is obtained after condensing the water; the separated oxygen carrier and carbon residue mixed solid matter enters the fluidized bed of the air reactor through the oxygen carrier circulation dipleg (4), and the oxygen carrier is regenerated to realize Oxygen. 2. The oxygen-carrying oxidation combustion method according to claim 1, characterized in that the metal oxide as the oxygen carrier is Fe ₂ O ₃ , FeO, Fe ₃ O ₄ , CuO, Cu ₂ O, NiO, ZnO, the metal element as the oxygen carrier is Fe, Cu, Zn, Ni. 3. oxygen carrier method according to claim 1, it is characterized in that the metal oxide of high valence state is reduced to the metal oxide of low valence state or metal simple substance, after fuel reactor fluidized bed upper riser fully reacts, Part of it enters another separator, and the separated clean carbon dioxide and water vapor mixture is discharged from the upper end (J2) of the separator, and the oxygen carrier and carbon residue mixed solids separated by the separator pass through the carbon residue circulation dipleg (5 -4), and then return to the gasification reaction chamber at the lower part of the fluidized bed of the fuel reactor to increase the carbon burnout rate. 4. A device for implementing the oxygen carrier method according to claim 1, characterized in that it consists of an air reactor fluidized bed (1), an oxygen-carrying heat-carrying return pipe (2), an oxygen carrier regeneration separator (3), an oxygen carrier regeneration return pipe (4) and a fuel reactor fluidized bed (5), the upper end of the air reactor fluidized bed (1) is connected with an oxygen-poor air separator (1-1), The discharge port at the lower end of the oxygen-poor air separator (1-1) is connected to one end of the oxygen-carrying heat-carrying return pipe (2), and the other end of the oxygen-carrying heat-carrying return pipe (2) is connected to the fuel reactor fluidized bed ( 5), the upper end of the fuel reactor fluidized bed (5) is connected to the upper end of the oxygen carrier regeneration separator (3), and the lower end of the oxygen carrier regeneration separator (3) is connected to the oxygen carrier regeneration return pipe ( 4) are connected at one end, and the other end of the oxygen carrier regeneration return pipe (4) is connected with the lower part of the air reactor fluidized bed (1). 5. The device according to claim 4, characterized in that an oxygen carrier replenishment port (B) is provided at the lower end of the air reactor circulating fluidized bed (1). 6. device according to claim 4, it is characterized in that in fuel reactor circulating fluidized bed (5) is made up of riser type, mixed gasification reaction chamber (5-3) and transition section (5-2), The riser type is connected with the mixed gasification reaction chamber (5-3) through a transition section (5-2). 7. The device according to claim 4, characterized in that the upper outlet of the first-level oxygen-poor air separator (1-1) is communicated with a secondary oxygen-depleted air separator (1-2), and the secondary oxygen-depleted air separation The upper end of the device (1-2) is provided with an oxygen-deficient air outlet (H), the lower end of the first-stage oxygen-deficient air separator (1-1) is connected with an oxygen carrier return leg (1-3), and the second-stage oxygen-deficient air separator The lower part of (1-2) communicates with the oxygen carrier return leg (1-3), and the lower end of the oxygen carrier return leg (1-3) is connected with a moving bed (1-4), and the moving bed (1-4 ) is provided with a fluidization air inlet (A) at the lower end, and a material outlet is provided at the lower part of the moving bed (1-4), and the material outlet is used as the lower discharge port of the oxygen-poor air separator (1-1). 8. device according to claim 4, is characterized in that being also connected with residual carbon separator at the upper end of fuel reactor fluidized bed (5), this residual carbon separator consists of one-stage flue gas residual carbon separator (5) -1) and the secondary flue gas carbon residue separator (5-5), the lower end of the primary flue gas carbon residue separator (5-1) is connected with a carbon residue return leg (5-6), and the carbon residue return leg (5-6) communicates with the outlet of the secondary flue gas carbon residue separator (5-5), and the lower end of the carbon residue return leg (5-6) is connected with the moving bed (5-7), and the moving bed (5-7) The lower end is provided with a fluidization air inlet (G), and the lower part of the moving bed (5-7) is provided with a material outlet, which communicates with the lower part of the reactor fluidized bed (5) through a circulation return pipe (5-4). 9. The device according to claim 4, characterized in that the oxygen carrier regeneration separator (3) consists of a primary flue gas oxygen carrier regeneration separator (3-1) and a secondary flue gas oxygen carrier regeneration separator Composition of (3-2), the outlet of the primary flue gas oxygen carrier regeneration separator (3-1) and the secondary flue gas oxygen carrier regeneration separator (3-2) are connected, and the primary flue gas oxygen carrier regeneration separation The outlet of the device (3-1) is connected with an oxygen carrier regeneration return leg, and the lower end of the oxygen carrier regeneration return leg (3) is connected with a moving bed (3-3), and the lower end of the moving bed (3-3) is provided with The fluidization air inlet (D), the lower part of the moving bed (3-3) is provided with a material outlet and the material outlet is connected to one end of the oxygen carrier regeneration return pipe (4).

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