CN101666546B - Pulverized coal combustion method and device with function of capturing CO2 - Google Patents

Abstract

Translated fromChinese

本发明提供了一种具有CO₂捕获功能的煤粉燃烧方法，对CuFe₂O₄进行分解生成O₂和氧缺位铁酸盐CuFe₂O₄-δ(0≤δ≤2)，气化后的煤粉与氧缺位铁酸盐发生氧化反应生成CO₂、H₂O和不凝结气体，其中不凝结气体与分解得到的O₂进行氧化反应生成CO₂、水蒸气。实现上述方法的装置包括由快速流化床、第一旋风分离器、两段式鼓泡流化床、U型流动密封阀和快速流化床依次连通构成的回路，鼓泡流化床还与第二旋风分离器连通，第二旋风分离器连通捕灰器。本发明将煤的纯氧燃烧技术和化学链燃烧技术有效结合，既克服纯O₂的制备成本，又充分实现煤反应后高浓度CO₂的分离。

The present invention provides a pulverized coal combustion method with CO₂ capture function, which decomposes CuFe₂ O₄ to generate O₂ and oxygen-deficient ferrite CuFe₂ O₄ -δ (0≤δ≤2), gasification The post-oxidation reaction between pulverized coal and oxygen-deficient ferrite generates CO₂ , H₂ O and non-condensable gas, wherein the non-condensable gas undergoes oxidation reaction with the decomposed O₂ to generate CO₂ and water vapor. The device for realizing the above method comprises a circuit composed of fast fluidized bed, first cyclone separator, two-stage bubbling fluidized bed, U-shaped flow sealing valve and fast fluidized bed, and the bubbling fluidized bed is also connected with The second cyclone separator is connected, and the second cyclone separator is connected to the ash catcher. The invention effectively combines the coal pure oxygen combustion technology and the chemical chain combustion technology, not only overcomes the preparation cost of pure_O2 , but also fully realizes the separation of high-concentration_CO2 after coal reaction.

Description

Translated fromChinese

具有CO₂捕获功能的煤粉燃烧方法及装置Pulverized coal combustion method and device with CO₂ capture function

技术领域technical field

本发明涉及一种煤粉燃烧方法及装置。The invention relates to a pulverized coal combustion method and device.

背景技术Background technique

随着能源需求的快速增长和化石燃料使用量的急剧增加，导致温室气体CO₂在自然界的累积量不断加大，控制化石燃料燃烧过程CO₂的排放，对于应对温室效应和全球变暖具有重要的作用。特别是对于中国，鉴于其能源结构以煤为主的特点，CO₂排放水平急剧增加并已经居于世界第二位的现状，开发高效的燃煤CO₂减排技术，控制我国燃煤CO₂排放水平，具有重大的社会意义和经济价值。With the rapid growth of energy demand and the sharp increase in the use of fossil fuels, the accumulation of greenhouse gas CO₂ in nature continues to increase. Controlling the emission of CO₂ in the process of burning fossil fuels is of great importance for coping with the greenhouse effect and global warming. role. Especially for China, in view of the characteristics of its energy structure dominated by coal, the level of CO₂ emissions has increased sharply and has already ranked second in the world, and it is necessary to develop efficient coal-fired CO₂ emission reduction technologies to control China's coal-fired CO₂ emissions It has great social significance and economic value.

传统的煤粉燃烧技术中，由于空气中N₂对于煤燃烧尾气的稀释，导致燃煤尾气中CO₂的体积份额只有15％左右，因此要从大流量和低CO₂体积份额的烟气中对CO₂进行捕获分离，需要耗费大量的成本和能量。鉴于此，用从空气中分离的纯O₂代替助燃空气作为氧化剂的纯氧燃烧技术，可以使煤燃烧反应尾气中CO₂的体积浓度高达90-95％，从而以较小的代价冷凝压缩后实现CO₂的永久封存。但是，该技术的主要缺点是，空气分离制备高纯O₂的投资大、能耗高。In the traditional pulverized coal combustion technology, due to the dilution of coal combustion tail gas by N₂ in the air, the volume fraction of CO₂ in the coal combustion tail gas is only about 15%, so it is necessary to start from the flue gas with large flow rate and low CO₂ volume fraction The capture and separation of CO₂ requires a lot of cost and energy. In view of this, the pure oxygen combustion technology that uses pure_O2 separated from the air to replace the combustion air as the oxidant can make the volume concentration of_CO2 in the tail gas of coal combustion reaction as high as 90-95%, so that it can be condensed and compressed at a small cost Realize the permanent sequestration of_CO2 . However, the main disadvantage of this technology is that the preparation of high-purity_O2 by air separation requires large investment and high energy consumption.

与上述的纯氧燃烧技术不同，直接以煤为燃料的化学链燃烧技术，首先由金属氧化物作为氧载体，与煤及其气化产物在燃料反应器中进行还原反应，被还原的氧载体再传递送入空气反应器中进行氧化再生。相对于纯氧燃烧技术，该技术具有显著的特点和优势，不仅能够根除煤在传统燃烧反应过程中产生的NOx，提高煤的利用效率；同时，当煤与氧载体完全反应时，反应产物仅包含CO₂和水蒸气，无需额外的分离装置和措施，经过简单冷凝处理，就可以得到高纯CO₂，便于后续存贮处理。但以煤为燃料时，由于煤气化速率比氧载体与煤气化产物反应的速率低得多，导致煤与氧载体反应不完全，煤反应尾气中含有CO、H₂和CH₄等不凝气体，给尾气中CO₂的分离造成很大的困难和障碍。Different from the pure oxygen combustion technology mentioned above, the chemical looping combustion technology that directly uses coal as fuel first uses metal oxides as oxygen carriers, and undergoes a reduction reaction with coal and its gasification products in the fuel reactor, and the reduced oxygen carriers Then transfer to the air reactor for oxidation regeneration. Compared with pure oxygen combustion technology, this technology has significant features and advantages. It can not only eradicate the NOx produced by coal in the traditional combustion reaction process, but also improve the utilization efficiency of coal; at the same time, when the coal and oxygen carrier completely react, the reaction product is only Containing CO₂ and water vapor, without additional separation devices and measures, high-purity CO₂ can be obtained after simple condensation treatment, which is convenient for subsequent storage and treatment. But when coal is used as fuel, because the gasification rate of coal is much lower than the reaction rate of oxygen carrier and coal gasification product, the reaction between coal and oxygen carrier is incomplete, and the tail gas of coal reaction contains non-condensable gases such as CO, H₂ and CH₄ , causing great difficulties and obstacles to the separation of CO₂ in the tail gas.

发明内容Contents of the invention

本发明的目的在于提供一种具有CO₂捕获功能的煤粉燃烧方法及装置，将煤的纯氧燃烧技术和化学链燃烧技术有效结合，既克服纯O₂的制备成本，又实现煤反应后高浓度CO₂的高效分离。The purpose of the present invention is to provide a pulverized coal combustion method and device with_CO2 capture function, which effectively combines the pure oxygen combustion technology of coal with the chemical looping combustion technology, which not only overcomes the preparation cost of pure_O2 , but also realizes the post-coal reaction Efficient separation of high-concentration_CO2 .

一种具有CO₂捕获功能的煤粉燃烧方法，对CuFe₂O₄进行分解生成O₂和氧缺位铁酸盐，氧缺位铁酸盐与气化后的煤粉发生还原反应生成CO₂、H₂O和不凝结气体，不凝结气体再与分解得到的O₂进行氧化反应生成CO₂和H₂O。A pulverized coal combustion method with CO₂ capture function, decomposes CuFe₂ O₄ to generate O₂ and oxygen-deficient ferrite, and the oxygen-deficient ferrite reacts with gasified coal powder to generate CO₂ , H₂ O and non-condensable gas, and the non-condensable gas is oxidized with the decomposed O₂ to generate CO₂ and H₂ O.

一种实现上述煤粉燃烧方法的装置，包括由快速流化床1、第一旋风分离器2、鼓泡流化床3的上半段、鼓泡流化床3的下半段、U型流动密封阀4和快速流化床1依次连通构成的回路；鼓泡流化床3的上半段还与第二旋风分离器5连通，第二旋风分离器5连通捕灰器6；鼓泡流化床3的上半段和下半段的相接处为束腰式结构。A device for realizing the above pulverized coal combustion method, comprising a fast fluidizedbed 1, afirst cyclone separator 2, the upper half of the bubbling fluidizedbed 3, the lower half of the bubbling fluidizedbed 3, a U-shaped Theflow sealing valve 4 and the rapid fluidizedbed 1 are connected in turn to form a circuit; the upper half of the bubbling fluidizedbed 3 is also connected to thesecond cyclone separator 5, and thesecond cyclone separator 5 is connected to theash catcher 6; The junction of the upper half and the lower half of the fluidizedbed 3 is a waist structure.

本发明的技术效果体现在：本发明在两段式鼓泡流化床反应器中，以CuFe₂O₄为氧载体，使得CuFe₂O₄分解释放出纯O₂气、CuFe₂O₄氧载体与煤及其气化产物的还原反应、煤未充分反应所释放出的不凝气体(包括CO、H₂和CH₄等)与纯O₂气的充分氧化等过程能够在同一反应装置中有效进行，克服了煤纯氧燃烧技术中制造纯氧过程能耗大、成本高的缺陷，煤化学链燃烧技术中煤利用效率低等诸多弊端，把煤的纯氧燃烧技术和煤的化学链燃烧技术有机的结合起来，而煤反应后所得到的是CO₂和水蒸气，经过冷凝分离后，可以得到高浓度的CO₂气体，便于后续存贮处理，从而有效的防止了燃煤尾气排空时所造成的大气中CO₂的浓度水平的急剧增加，对于实现煤的洁净利用，高浓度CO₂的高效低能耗捕获，燃煤CO₂排放水平及大气中CO₂浓度水平的有效降低，温室效应和全球变暖的的抵制，具有深远的社会意义和经济价值。The technical effect of the present invention is embodied in: the present invention uses CuFe₂ O₄ as the oxygen carrier in the two-stage bubbling fluidized bed reactor, so that CuFe₂ O₄ decomposes and releases pure O₂ gas, CuFe₂ O₄ oxygen The reduction reaction of carrier and coal and its gasification products, the full oxidation of non-condensable gas (including CO,_H2 and_CH4, etc.) and pure_O2 gas released by incomplete reaction of coal can be carried out in the same reaction device Effectively, it overcomes the defects of high energy consumption and high cost in the process of producing pure oxygen in coal pure oxygen combustion technology, and many disadvantages such as low coal utilization efficiency in coal chemical chain combustion technology. Combustion technology is organically combined, and what is obtained after coal reaction is CO₂ and water vapor. After condensation and separation, high-concentration CO₂ gas can be obtained, which is convenient for subsequent storage and treatment, thus effectively preventing coal combustion tail gas emissions The sharp increase in the concentration of CO₂ in the atmosphere caused by space-time is beneficial to the clean utilization of coal, the efficient and low-energy capture of high-concentration CO₂ , the effective reduction of CO₂ emissions from coal combustion and the concentration of CO₂ in the atmosphere. The resistance to the greenhouse effect and global warming has far-reaching social significance and economic value.

附图说明Description of drawings

图1是本发明装置结构示意图。Fig. 1 is a schematic diagram of the structure of the device of the present invention.

具体实施方式Detailed ways

本发明所提出的具有CO₂捕获功能的新型煤粉利用装置，由快速流化床1、第一旋风分离器2、鼓泡流化床3、U型流动密封阀4、第二旋风分离器5以及捕灰器6组成。快速流化床1的上部与第一旋风分离器2连通，通过第一分离器2排出反应剩余空气，而第一旋风分离器2下部料腿与鼓泡流化床3的上半段相连通，煤反应尾气通过第二旋风分离器5排出，煤飞灰以及细小的氧载体颗粒通过捕灰器6进行收集，而该鼓泡流化床3的下半段则与U型流动密封阀4相连，再引入快速流化床1，完成氧载体的氧化再生以及后续的多次循环输送。鼓泡流化床采用两段式，上半段和下半段的相接处为束腰式结构，即该上半段的下口以及下半段的上口均逐渐向内收拢，使得相接处的截面积小于上，下段的截面积，这对于流化床气体流场的组织以及氧载体与煤颗粒的有效混合和充分反应，非常有利。The new pulverized coal utilization device with_CO2 capture function proposed by the present invention consists of a fast fluidizedbed 1, afirst cyclone separator 2, a bubbling fluidizedbed 3, a U-shapedflow sealing valve 4, and asecond cyclone separator 5 andash catcher 6 to form. The upper part of the fast fluidizedbed 1 communicates with thefirst cyclone separator 2, and the residual air of the reaction is discharged through thefirst separator 2, while the lower part of thefirst cyclone separator 2 communicates with the upper half of the bubbling fluidizedbed 3 , the coal reaction tail gas is discharged through thesecond cyclone separator 5, the coal fly ash and fine oxygen carrier particles are collected through theash catcher 6, and the lower half of the bubbling fluidizedbed 3 is connected to the U-shapedflow sealing valve 4 connected, and then introduced into the fast fluidizedbed 1 to complete the oxidation regeneration of the oxygen carrier and the subsequent multiple cycle transportation. The bubbling fluidized bed adopts a two-stage structure, and the junction of the upper half and the lower half is a waist structure, that is, the lower opening of the upper half and the upper opening of the lower half are gradually retracted inward, so that the relative The cross-sectional area of the joint is smaller than that of the upper and lower sections, which is very beneficial to the organization of the gas flow field of the fluidized bed and the effective mixing and full reaction of the oxygen carrier and the coal particles.

本发明所提出的具有CO₂捕获功能的新型煤粉利用技术，把CuFe₂O₄氧载体由大旋风分离器2输送进入鼓泡流化床反应器3的上段，完成CuFe₂O₄氧载体的纯O₂的分解释放，并在B区域形成富氧气氛；煤由CO₂气力输送进入该流化床反应器3的下半段，以水蒸气或者CO₂作为流化介质，通过该流化床反应器的底端进入，使煤进行充分气化，分解释放出氧气的CuFe₂O₄氧载体(氧缺位铁酸盐)则与煤及其气化产物在C区域进行还原反应，反应气体流过该流化床的上半段时与CuFe₂O₄分解释放出的纯O₂在B区域进一步进行纯氧燃烧，尾气通过小旋风分离器5排出，其中的水蒸气经过冷凝分离就可以得到高浓度CO₂，而被分离的飞灰和氧载体细颗粒则通过捕灰器6进行收集。同时，在该流化床3下半段被还原的氧载体CuFe₂O₄，则传递进入U型流动密封阀4，在水蒸气的流化下，使得煤焦颗粒以及氧载体颗粒进一步反应，尽量避免CO₂泄露进入快速流化床1中，而被还原的氧缺位铁酸盐则进一步通过U型流动密封阀4进入快速流化床1，其与空气氧化反应再生为CuFe₂O₄，从而完成以CuFe₂O₄为氧载体以煤为燃料的整个化学链燃烧过程。以此，使CuFe₂O₄分解释放出纯O₂、CuFe₂O₄氧载体与煤及其气化产物的还原反应、以及煤未充分反应所释放出的不凝气体(包括CO、H₂和CH₄等)与纯O₂的充分氧化等诸多反应过程，集成在同一个反应器中并分阶段有效进行，从而把煤与纯O₂的纯氧燃烧技术以及煤与金属氧载体的化学链燃烧技术有机结合。The new pulverized coal utilization technology with_CO2 capture function proposed by the present invention transports the_{CuFe2O4oxygen} carrier from thelarge cyclone separator 2 into the upper section of the bubbling fluidizedbed reactor 3 to complete the_{CuFe2O4oxygen} carrier The decomposition and release of pure O₂ forms an oxygen-enriched atmosphere in area B; the coal is pneumatically transported by CO₂ into the lower half of thefluidized bed reactor 3, with water vapor or CO₂ as the The bottom of the chemical bed reactor enters to fully gasify the coal, and the CuFe₂ O₄ oxygen carrier (oxygen-deficient ferrite) that decomposes and releases oxygen undergoes a reduction reaction with the coal and its gasification products in the C area. When the reaction gas flows through the upper half of the fluidized bed, it decomposes with CuFe₂ O₄ and releases pure O₂ for further pure oxygen combustion in the B area, and the tail gas is discharged through thesmall cyclone separator 5, and the water vapor in it is condensed and separated A high concentration of CO₂ can be obtained, while the separated fly ash and oxygen carrier fine particles are collected by theash catcher 6 . At the same time, the reduced oxygen carrier CuFe₂ O₄ in the lower half of the fluidizedbed 3 is passed into the U-shapedflow sealing valve 4, and under the fluidization of water vapor, the coal char particles and the oxygen carrier particles are further reacted, Try to avoid CO₂ leakage into the fast fluidizedbed 1, while the reduced oxygen-deficient ferrite further enters the fast fluidizedbed 1 through the U-shapedflow sealing valve 4, and it reacts with air oxidation to regenerate CuFe₂ O₄ , so as to complete the whole chemical chain combustion process with CuFe₂ O₄ as oxygen carrier and coal as fuel. In this way, CuFe₂ O₄ is decomposed to release pure O₂ , the reduction reaction of CuFe₂ O₄ oxygen carrier with coal and its gasification products, and the non-condensable gas (including CO, H₂ and CH₄ , etc.) and pure O₂ and many other reaction processes are integrated in the same reactor and carried out effectively in stages, so that the pure oxygen combustion technology of coal and pure O₂ and the chemistry of coal and metal oxygen carriers The chain combustion technology is organically combined.

CuFe₂O₄分解得到的氧缺位铁酸盐CuFe₂O_4-δ(0≤δ≤2)返回快速流化床1，其与空气充分氧化再生为氧载体CuFe₂O₄，并吸收该反应释放出的大量的热量，然后携带大量热量的再生CuFe₂O₄氧载体通过第一旋风分离器2进入鼓泡流化床3的上半段，利用其所携带的大量热量，并在煤与原有CuFe₂O₄反应产物所形成的还原性气氛下，分解释放出纯O₂，从而完成该氧载体的多次循环利用。The oxygen-deficient ferrite CuFe₂ O_4-δ (0≤δ≤2) obtained from the decomposition of CuFe₂ O 4 is returned to the fast fluidizedbed 1, where it is fully oxidized with air to regenerate the oxygen carrier CuFe₂ O₄ , and absorbs the The reaction releases a large amount of heat, and then the regenerated CuFe₂ O₄ oxygen carrier that carries a large amount of heat enters the upper half of the bubbling fluidizedbed 3 through thefirst cyclone separator 2, utilizes the large amount of heat it carries, and in the coal Under the reducing atmosphere formed by the reaction product with the original CuFe₂ O₄ , it decomposes and releases pure O₂ , thereby completing the multiple recycling of the oxygen carrier.

Claims (2)

Translated fromChinese

1.一种具有CO₂捕获功能的煤粉燃烧方法，对CuFe₂O₄进行分解生成O₂和氧缺位铁酸盐，气化后的煤粉与氧缺位铁酸盐发生氧化反应生成CO_2、H₂O和不凝结气体，不凝结气体与分解得到的O₂再进行氧化反应生成CO₂和水蒸汽。1. A pulverized coal combustion method with_CO2 capture function, decomposing_CuFe2O4 to generate_O2 and oxygen-deficient ferrite, and_the gasified coal powder and oxygen-deficient ferrite undergo oxidation reaction to form CO_{2 ,} H₂ O and non-condensable gas, the non-condensable gas and the decomposed O₂ undergo oxidation reaction to generate CO₂ and water vapor.2.一种实现权利要求1所述的具有CO₂捕获功能的煤粉燃烧方法的装置，包括由快速流化床（1）、第一旋风分离器（2）、鼓泡流化床（3）的上半段、鼓泡流化床（3）的下半段、U型流动密封阀（4）和快速流化床（1）依次连通构成的回路；鼓泡流化床（3）的上半段还与第二旋风分离器（5）连通，第二旋风分离器（5）连通捕灰器（6）；鼓泡流化床（3）的上半段和下半段的相接处为束腰式结构。2. A device for realizing the pulverized coal combustion method with_CO capture function as claimed in claim 1, comprising a fast fluidized bed (1), a first cyclone separator (2), a bubbling fluidized bed (3 ), the lower half of the bubbling fluidized bed (3), the U-shaped flow sealing valve (4) and the fast fluidized bed (1) are sequentially connected to form a circuit; the bubbling fluidized bed (3) The upper half is also connected with the second cyclone separator (5), and the second cyclone separator (5) is connected with the ash catcher (6); the connection between the upper half and the lower half of the bubbling fluidized bed (3) It is a waist structure.

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