CN101666546A

CN101666546A - Pulverized coal combustion method and device with function of capturing CO2

Info

Publication number: CN101666546A
Application number: CN200910272355A
Authority: CN
Inventors: 王保文; 赵海波; 张少华; 郑楚光
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2009-09-30
Filing date: 2009-09-30
Publication date: 2010-03-10
Anticipated expiration: 2029-09-30
Also published as: CN101666546B

Abstract

The invention provides a pulverized coal combustion method with the function of capturing CO2, comprising the steps: CuFe2O4 is decomposed to generate O2 and oxygen vacancy ferrite CuFe2O4-delta (delta is no less than 0 but no more than 2); oxidation reaction is generated between the pulverized coal and the oxygen vacancy ferrite so as to generate CO2, H2O and non-condensed gas, wherein the oxidation reaction is generated between the non-condensed gas and O2 which is obtained by decomposition so as to generate CO2 and steam. The device for achieving the method comprises a loop which is formedby the communication of a fast fluidized bed, a first cyclone separator, a two-stage type bubbling fluidized bed, a U-type flow seal valve and the fast fluidized bed in sequence; and the bubbling fluidized bed is also communicated with a second cyclone separator which is communicated with an ash catching device. The pulverized coal combustion method with the function of capturing CO2 effectively combines a pure oxygen combustion technology of coal with a chemical chain combustion technology, not only lowers the preparation cost of the pure CO2, but also fully realizes the separation of the high-concentration CO2 after the coal reaction.

Description

Has CO 2The coal dust combustion method of capturing function and device

Technical field

The present invention relates to a kind of coal dust combustion method and device.

Background technology

Along with the rapid growth of energy demand and the rapid increase of fossil fuel use amount, cause greenhouse gases CO ₂Continue to increase control combustion of fossil fuel process CO in natural cumulant ₂Discharging, have important effect for reply greenhouse effects and global warming.Particularly for China, in view of its energy resource structure take coal as main characteristics, CO ₂Emission level sharply increases and has occupy the present situation of second place of the world, develops efficient coal-fired CO ₂Emission-reduction technology, the coal-fired CO of control China ₂Emission level has great social effect and economic worth.

In traditional pulverized coal combustion, because N in the air ₂For the dilution of coal combustion tail gas, cause CO in the fire coal tail gas ₂Volume share have only about 15%, therefore will be from big flow and low CO ₂In the flue gas of volume share to CO ₂Catch separation, need expend a large amount of costs and energy.Given this, use the pure O that from air, separates ₂Replace combustion air as the Pure Oxygen Combustion Technology of oxidant, can make CO in the coal combustion reaction end gas ₂Volumetric concentration up to 90-95%, thereby to realize CO after the littler cost condensation compression ₂forever seal up for safekeeping.But the major defect of this technology is that air separation prepares high-purity O ₂Investment big, energy consumption is high.

Different with above-mentioned pure oxygen burning technology, be the chemical chain burning technology of fuel directly with the coal, at first by metal oxide as the carrier of oxygen, in the fuel reaction device, carry out reduction reaction with coal and gasification product thereof, the carrier of oxygen that is reduced transmits to send into again and carries out oxidation regeneration in the air reactor.With respect to Pure Oxygen Combustion Technology, this technology has outstanding feature and advantage, not only can eradicate the NOx that coal produces in the traditional combustion course of reaction, improves the utilization ratio of coal; Simultaneously, when coal and carrier of oxygen complete reaction, product only comprises CO ₂And steam, need not extra separator and measure, process through simple condensation, just can obtain high-purity CO ₂, be convenient to follow-up storage and process.But when being fuel,, cause the reaction of the coal and the carrier of oxygen not exclusively, contain CO, H in the coal reaction end gas because the speed of the coal gasification speed ratio carrier of oxygen and the reaction of coal gasification product is much lower with the coal ₂And CH ₄Deng on-condensible gas, give CO in the tail gas ₂Separation cause very big difficulty and obstacle.

Summary of the invention

The object of the present invention is to provide a kind of CO of having ₂The coal dust combustion method of capturing function and device, pure oxygen burning technology and the effective combination of chemical chain burning technology with coal had both overcome pure O ₂Preparation cost, realize coal reaction back high concentration CO again ₂Efficient separation.

A kind of have a CO ₂The coal dust combustion method of capturing function is to CuFe ₂O ₄Decompose and generate O ₂With the oxygen vacancy ferrite, the coal dust generation reduction reaction after oxygen vacancy ferrite and the gasification generates CO ₂, H ₂The O that O and incondensable gas, incondensable gas obtain with decomposition again ₂Carry out oxidation reaction and generate CO ₂And H ₂O.

A kind of device of realizing above-mentioned coal dust combustion method comprises by the upper semisection of fast fluidized bed 1, first cyclone separator 2, bubbling fluidized bed 3, lower semisection, U type loop seal 4 and the fast fluidized bed 1 of bubbling fluidized bed 3 being communicated with the loop that constitutes successively; The upper semisection of bubbling fluidized bed 3 also is communicated with second cyclone separator 5, and second cyclone separator 5 is communicated with ash catcher 6; The upper semisection of bubbling fluidized bed 3 and the joint of lower semisection are the girdling type structure.

Technique effect of the present invention is embodied in: the present invention is in two-part bubbling fluidization bed bioreactor, with CuFe ₂O ₄Be the carrier of oxygen, so that CuFe ₂O ₄Decompose and discharge pure O ₂Gas, CuFe ₂O ₄The reduction reaction of the carrier of oxygen and coal and gasification product thereof, coal fully do not react the on-condensible gas that discharges and (comprise CO, H ₂And CH ₄Deng) and pure O ₂The processes such as the abundant oxidation of gas can effectively be carried out in same reaction unit, overcome and made the defective that pure oxygen process energy consumption is big, cost is high in the coal Pure Oxygen Combustion Technology, many drawbacks such as coal utilization efficient is low in the coal chemistry chain burning technology, the chemical chain burning technology of the Pure Oxygen Combustion Technology of coal and coal is organically combined, and resulting after the coal reaction be CO ₂And steam, through after the condensation separation, can obtain the CO of high concentration ₂Gas is convenient to follow-up storage and is processed, thereby has effectively prevented CO in the atmosphere that fire coal tail gas causes when emptying ₂The rapid increase of concentration level, for the clean utilization of realizing coal, high concentration CO ₂High-efficiency low energy consumption catch coal-fired CO ₂CO in emission level and the atmosphere ₂Effective reduction of concentration level, greenhouse effects and global warming resistance, have far-reaching social effect and economic worth.

Description of drawings

Fig. 1 is apparatus of the present invention structural representations.

The specific embodiment

Proposed by the invention have a CO ₂The new coal powder use device of capturing function is made up of fast fluidized bed 1, first cyclone separator 2, bubbling fluidized bed 3, U type loop seal 4, second cyclone separator 5 and ash catcher 6.The top of fast fluidized bed 1 is communicated with first cyclone separator 2, discharge the reaction surplus air by first separator 2, and first cyclone separator, 2 bottom diplegs are connected with the upper semisection of bubbling fluidized bed 3, the coal reaction end gas is discharged by second cyclone separator 5, coal fly ash and tiny carrier of oxygen particle are collected by ash catcher 6, the lower semisection of this bubbling fluidized bed 3 then links to each other with U type loop seal 4, introduce fast fluidized bed 1 again, finish the oxidation regeneration of the carrier of oxygen and follow-up repeatedly circulation and carry.Bubbling fluidized bed adopts two-part, the joint of upper semisection and lower semisection is the girdling type structure, promptly the suitable for reading of the end opening of this upper semisection and lower semisection all inwardly drawn in gradually, make the sectional area of joint less than last, the sectional area of hypomere, this tissue and carrier of oxygen for the fluidized bed gas flow field mixes and fully reaction with the effective of coal particle, and is highly beneficial.

Proposed by the invention have a CO ₂The new coal powder of capturing function is utilized technology, CuFe ₂O ₄The carrier of oxygen delivers into the epimere of bubbling fluidization bed bioreactor 3 by willy-willy separator 2, finishes CuFe ₂O ₄The pure O of the carrier of oxygen ₂Decomposition discharge, and form oxygen-enriched atmosphere in the B zone; Coal is by CO ₂Pneumatic transporting is fed into the lower semisection of this fluidized-bed reactor 3, with steam or CO ₂As fluidizing agent, the bottom by this fluidized-bed reactor enters, and coal is fully gasified, and decomposes the CuFe that discharges oxygen ₂O ₄The carrier of oxygen (oxygen vacancy ferrite) then carries out reduction reaction with coal and gasification product thereof in the C zone, when reacting gas flows through the upper semisection of this fluid bed and CuFe ₂O ₄Decompose the pure O that discharges ₂Further carry out pure oxygen burning in the B zone, tail gas is discharged by whirly separator 5, and steam wherein just can obtain high concentration CO through condensation separation ₂, separated flying dust and carrier of oxygen fine grained are then collected by ash catcher 6.Simultaneously, the carrier of oxygen CuFe that is reduced at these fluid bed 3 lower semisections ₂O ₄, then transmit and enter U-shaped loop seal 4, under the fluidisation of steam, so that Coal Char Particles and carrier of oxygen particle further react, avoid CO as far as possible ₂Leakage enters in the fast fluidized bed 1, and the oxygen vacancy ferrite that is reduced then further enters fast fluidized bed 1 by U-shaped loop seal 4, and itself and air oxidation reaction are regenerated as CuFe ₂O ₄Thereby, finish with CuFe ₂O ₄Be the whole burning chemistry chains process of the carrier of oxygen take coal as fuel.With this, make CuFe ₂O ₄Decompose and discharge pure O ₂, CuFe ₂O ₄The reduction reaction of the carrier of oxygen and coal and gasification product thereof and coal fully do not react the on-condensible gas that discharges and (comprise CO, H ₂And CH ₄Deng) and pure O ₂Many courses of reaction such as abundant oxidation, be integrated in the same reactor and effectively carry out stage by stage, thus coal and pure O ₂Pure Oxygen Combustion Technology and the chemical chain burning technology of coal and metal oxygen carrier organically combine.

CuFe ₂O ₄Decompose the oxygen vacancy ferrite CuFe that obtains ₂O _4-δ(0≤δ≤2) return fast fluidized bed 1, and itself and the abundant oxidation regeneration of air are carrier of oxygen CuFe ₂O ₄, and absorb a large amount of heat that this reaction discharges, carry then the regeneration CuFe of amount of heat ₂O ₄The carrier of oxygen enters the upper semisection of bubbling fluidized bed 3 by first cyclone separator 2, utilizes its entrained amount of heat, and at coal and original CuFe ₂O ₄Under the formed reducing atmosphere of product, decomposition discharges pure O ₂Thereby, finish the recycled for multiple times of this carrier of oxygen.

Claims

1, a kind of have a CO ₂The coal dust combustion method of capturing function is to CuFe ₂O ₄Decompose and generate O ₂With the oxygen vacancy ferrite, the coal dust after the gasification and oxygen vacancy ferrite generation oxidation reaction generate CO ₂, H ₂O and incondensable gas, the O that incondensable gas and decomposition obtain ₂Carry out again oxidation reaction and generate CO ₂And water vapour.

2, a kind of device of realizing above-mentioned coal dust combustion method comprises by the upper semisection of fast fluidized bed (1), first cyclone separator (2), bubbling fluidized bed (3), lower semisection, U type loop seal (4) and the fast fluidized bed (1) of bubbling fluidized bed (3) being communicated with the loop that constitutes successively; The upper semisection of bubbling fluidized bed (3) also is communicated with second cyclone separator (5), and second cyclone separator (5) is communicated with ash catcher (6); The upper semisection of bubbling fluidized bed (3) and the joint of lower semisection are the girdling type structure.