CN205746802U - Station boiler uses cyclone cylinder classification to realize the system of fuel denitration by refueling - Google Patents

Station boiler uses cyclone cylinder classification to realize the system of fuel denitration by refueling Download PDF

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CN205746802U
CN205746802U CN201620542244.7U CN201620542244U CN205746802U CN 205746802 U CN205746802 U CN 205746802U CN 201620542244 U CN201620542244 U CN 201620542244U CN 205746802 U CN205746802 U CN 205746802U
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fuel
cyclone
reburning
main
zone
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车得福
卜宇凡
吴松
唐春丽
邓磊
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Xian Jiaotong University
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Abstract

The utility model discloses a kind of station boiler uses cyclone cylinder classification to realize the system of fuel denitration by refueling.This system, based on cyclone firing mode and fuel reburning technology, including main combustion cyclone cylinder, main furnace chamber, fires cyclone cylinder or cyclone gasification furnace, fire air nozzle and slag tap equipment again.This utility model is by the way of using cyclone firing, it is ensured that catching fire and stable burning of fuel.On the basis of conventional fuel reburning technology, part of fuel is sent into fire again cyclone cylinder or cyclone gasification furnace carry out half gasification or the reaction that is gasified totally, using the high-temperature gas product of generation as reburning fuel, it is ensured that the quantity of reaction temperature required in reducing zone and effectively reduction group.Simultaneously because allow the fuel staging of deeper degree so that the reducing atmosphere of reducing zone has obtained further enhancing, improves the denitration efficiency of system, and the reburning fuel of gaseous state also makes the burning of burning-out zone be more prone to.

Description

电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统Power plant boiler adopts cyclone classification to realize fuel reburning and denitrification system

技术领域:Technical field:

本实用新型涉及一种电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统。The utility model relates to a system in which a boiler in a power station adopts cyclone classification to realize fuel reburning and denitrification.

背景技术:Background technique:

众所周知,氮氧化物(NOx)是煤燃烧过程中产生的主要污染物之一,近年来,NOx的危害受到全球各国越来越多的重视。为了降低煤电的污染物排放总量,国家环保部出台和颁布了“史上最严、世界范围内最严”的火电厂大气污染物排放标准(GB13223-2011),并于2012年1月1日起开始执行。新标准对燃煤锅炉NOx排放提出了十分严格的要求,不得超过100mg·m-3,同时对重点地区以气体为燃料的燃气轮机组提出了NOx排放不得超过50mg·m-3的特别排放限值要求。如此苛刻的排放限值使国内火电行业面临前所未有的压力和挑战。相比费用昂贵的选择性催化还原技术(SCR),通过燃烧技术的改进,在燃料燃烧过程中降低NOx的生成量是减少NOx排放最为理想和经济的途径。As we all know, nitrogen oxides (NO x ) are one of the main pollutants produced in the coal combustion process. In recent years, the harm of NO x has been paid more and more attention by countries all over the world. In order to reduce the total amount of pollutant emissions from coal-fired power plants, the Ministry of Environmental Protection issued and promulgated the "most stringent in history and the most stringent in the world" thermal power plant air pollutant emission standards (GB13223-2011), and on January 1, 2012 Started from the date. The new standard puts forward very strict requirements on the NOx emission of coal-fired boilers, which must not exceed 100mg·m -3 , and at the same time proposes a special NOx emission of no more than 50mg·m -3 for gas turbine units in key areas limit requirements. Such a stringent emission limit has brought unprecedented pressure and challenges to the domestic thermal power industry. Compared with the expensive Selective Catalytic Reduction (SCR), the improvement of combustion technology to reduce the amount of NO x generated during fuel combustion is the most ideal and economical way to reduce NO x emissions.

目前,国内已有一些通过组织燃烧来脱除NOx的相关技术,包括燃料浓淡分离、低NOx燃烧器、空气分级技术、燃料再燃技术、烟气再循环等。其中,燃料再燃技术是一种公认的非常有效的方法,其脱硝效率一般都在50%~70%。燃料再燃技术发展至今,其主要形式已基本固定,即在锅炉主炉膛内沿高度方向分为三个区域,第一区为主燃区,在这里仅送入锅炉大部分的燃料,约占总量的80%~85%,同时在氧化性或弱还原性气氛下燃烧并生成NOx;第二区为再燃区,送入剩余的15%~20%燃料,形成还原性气氛,在过量空气系数α<1的条件下将主燃区已生成的NOx还原成N2。燃料再燃技术的核心就是,在再燃区内不仅将已生成的NOx进行还原,而且还较为有效的抑制了新的NOx生成,使NOx的排放浓度进一步降低;第三区为燃尽区,此处通入燃尽风,过量空气系数α>1,以完成剩余燃料的燃尽。At present, there are some related technologies for removing NO x by organizing combustion in China, including fuel rich-lean separation, low NO x burner, air classification technology, fuel reburning technology, flue gas recirculation, etc. Among them, fuel reburning technology is recognized as a very effective method, and its denitrification efficiency is generally 50% to 70%. Since the development of fuel reburning technology, its main form has been basically fixed, that is, the main furnace of the boiler is divided into three areas along the height direction. The first area is the main combustion area, where only most of the fuel is fed into the boiler, accounting for about 80% to 85% of the fuel is burned in an oxidizing or weakly reducing atmosphere to generate NOx ; the second zone is a reburning zone, where the remaining 15% to 20% of fuel is fed to form a reducing atmosphere. Under the condition of coefficient α<1, the NO x generated in the main combustion zone is reduced to N 2 . The core of fuel reburning technology is that in the reburning zone, not only the generated NO x is reduced, but also the formation of new NO x is effectively suppressed, so that the emission concentration of NO x is further reduced; the third zone is the burnout zone , where the exhaust air is introduced, and the excess air coefficient α>1, in order to complete the burnout of the remaining fuel.

然而近几年在国内,燃料再燃技术的发展和应用却一度受阻,究其原因主要是在工程实际应用中存在以下几个方面的限制:However, in China in recent years, the development and application of fuel reburning technology has been hindered for a while. The main reason is that there are limitations in the following aspects in the actual engineering application:

(1)再燃燃料份额的限制(1) Restriction on the share of reburning fuel

为了增强燃料再燃技术对NOx的减排效果,必须在还原区内形成更强的还原性气氛,即需要进一步扩大再燃燃料所占的份额,然而对于传统的煤粉炉来说,再燃燃料份额扩大后会给燃尽区带来很大的燃尽问题,严重影响了燃料的燃烧效率。In order to enhance the NOx emission reduction effect of fuel reburning technology, a stronger reducing atmosphere must be formed in the reduction zone, that is, the share of reburning fuel needs to be further expanded. However, for traditional pulverized coal furnaces, the share of reburning fuel After the expansion, it will bring a great burnout problem to the burnout zone, which seriously affects the combustion efficiency of the fuel.

(2)再燃区长度的限制(2) Restriction on the length of the reburning zone

还原区的长度反映了燃料在还原区内的停留时间,是制约NOx还原效果的另一个重要因素,但是在工程实际中通过增大炉膛高度来满足这一要求的做法会使得整个系统的成本费用大大增加。The length of the reduction zone reflects the residence time of the fuel in the reduction zone, which is another important factor restricting the effect of NO x reduction. However, in engineering practice, increasing the height of the furnace to meet this requirement will increase the cost of the entire system. The cost has increased significantly.

(3)主燃区α的限制(3) Limitation of main combustion zone α

对于常规的燃料再燃技术,主燃区内80%~85%的燃料是在0.9~1.1的过量空气系数下完成燃烧的,在此过程中必然会生成较多的污染物NOx,然而如果试图通过降低过量空气系数α来增强主燃区的还原性,以此减少主燃区NOx的生成,那么主燃料在此处的着火和燃烧必然会受到显著影响。For the conventional fuel reburning technology, 80% to 85% of the fuel in the main combustion zone is burned at an excess air ratio of 0.9 to 1.1. During this process, more pollutants NO x will inevitably be generated. However, if you try to By reducing the excess air coefficient α to enhance the reducibility of the main combustion zone, thereby reducing the generation of NOx in the main combustion zone, the ignition and combustion of the main fuel here will definitely be significantly affected.

(4)再燃燃料种类的限制(4) Restrictions on the type of reburning fuel

根据国内已有的研究,为了在保证NOx减排效果的基础上进一步提高燃烧效率,学者们针对常规的燃料再燃技术提出采用超细煤粉或天然气(CH4)等作为再燃燃料的改进方法,这样对于整体的燃烧经济性的确有很大提升。但是超细煤粉的制备所带来的电耗和复杂制粉系统的运行费用都会大大提高成本,同时天然气等气体燃料的大量获取也受到很大的地域限制。According to the existing domestic research, in order to further improve the combustion efficiency on the basis of ensuring the NO x emission reduction effect, scholars have proposed an improved method of using ultra-fine coal or natural gas (CH 4 ) as the reburning fuel for the conventional fuel reburning technology , so that the overall combustion economy is indeed greatly improved. However, the power consumption brought about by the preparation of ultra-fine coal powder and the operating cost of the complex pulverization system will greatly increase the cost. At the same time, the large-scale acquisition of gaseous fuels such as natural gas is also subject to great geographical restrictions.

实用新型内容:Utility model content:

针对目前已有的燃料再燃技术在脱硝方面所存在的不足之处,本实用新型提供了一种电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统。其目的在于,克服常规燃料再燃技术的缺点,在兼顾燃料较高燃烧效率的基础上,进一步降低煤粉燃烧锅炉的NOx排放。Aiming at the deficiencies in denitrification of the existing fuel reburning technology, the utility model provides a system in which a power station boiler adopts cyclone classification to realize fuel reburning and denitrification. Its purpose is to overcome the shortcomings of conventional fuel reburning technology, and further reduce the NOx emission of pulverized coal combustion boilers on the basis of taking into account the high combustion efficiency of fuel.

为达到上述目的,本实用新型采用如下技术方案来实现的:In order to achieve the above object, the utility model adopts the following technical solutions to realize:

电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统,包括主燃旋风筒(1)、主炉膛(2)以及再燃旋风筒或旋风气化炉(3);其中,Power plant boiler adopts cyclone classification to realize fuel reburning and denitrification system, including main combustion cyclone (1), main furnace (2) and reburning cyclone or cyclone gasifier (3); among them,

主炉膛(2)自下而上依次分为主燃区、再燃区和燃尽区,在主炉膛(2)主燃区周向上布置有主燃旋风筒(1),主炉膛(2)再燃区的再燃燃料喷口(4)处布置有再燃旋风筒或旋风气化炉(3),主炉膛(2)燃尽区周向上布置有燃尽风喷口(5)。The main furnace (2) is divided into main combustion zone, reburning zone and burnout zone from bottom to top. A main combustion cyclone (1) is arranged on the circumference of the main combustion zone of the main furnace (2), and the main furnace (2) reburns A reburning cyclone or cyclone gasifier (3) is arranged at the reburning fuel nozzle (4) in the zone, and an overburning air nozzle (5) is arranged on the circumference of the burnout zone of the main furnace (2).

本实用新型进一步的改进在于:主炉膛(2)底部布置有渐缩状结构的液态排渣设备(9)。The further improvement of the utility model is that: the bottom of the main furnace (2) is arranged with a liquid slagging device (9) with a tapered structure.

本实用新型进一步的改进在于:主燃旋风筒(1)的一端设置有主燃料一次风喷口(6),另一端设置有旋风筒凹形出口(8)并与主炉膛相连通,主燃旋风筒(1)的周向上设置有主燃区二次切向风喷口(7)。The further improvement of the utility model is that: one end of the main combustion cyclone (1) is provided with a main fuel primary air nozzle (6), and the other end is provided with a cyclone concave outlet (8) and communicated with the main furnace, and the main combustion cyclone The cylinder (1) is provided with a secondary tangential air nozzle (7) in the main combustion zone on the circumferential direction.

与现有技术相比,本实用新型提出了一种电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统,具有以下优点:Compared with the prior art, the utility model proposes a power plant boiler adopting cyclone classification to realize fuel reburning and denitrification system, which has the following advantages:

1、得益于旋风筒中优良的着火燃烧条件,相比常规燃料再燃技术,主燃区可以创造相对更小的过量空气系数α,这样既有效抑制了主燃区NOx的大量生成,同时又不会影响筒内主燃料的稳定燃烧。1. Thanks to the excellent ignition and combustion conditions in the cyclone, compared with the conventional fuel reburning technology, the main combustion zone can create a relatively smaller excess air coefficient α, which not only effectively suppresses the massive generation of NO x in the main combustion zone, but also It will not affect the stable combustion of the main fuel in the barrel.

2、当电站锅炉中采用旋风炉时,往往一台锅炉可以有数只到数十只旋风筒不等,本实用新型相比原有的电站锅炉系统,减少了主燃区旋风筒的数量,同时在再燃燃料喷口处布置有1~2个再燃旋风筒或旋风气化炉,这样完全不会使系统变得更加复杂,在锅炉制造方面也不会带来成本增加的问题。2. When cyclone furnaces are used in power plant boilers, often one boiler may have several to dozens of cyclone tubes. Compared with the original power plant boiler system, the utility model reduces the number of cyclone tubes in the main combustion area, and at the same time One or two reburning cyclones or cyclone gasifiers are arranged at the reburning fuel nozzle, so that the system will not become more complicated at all, and the problem of cost increase in boiler manufacturing will not be brought about.

3、在本实用新型中,再燃燃料中含有大量具有还原性的可燃气体,既保证了还原区内NOx的还原效率,又使得燃尽区剩余燃料的燃烧更加容易,最重要的是,这种方法解决了常规燃料再燃技术中获取超细煤粉和天然气等再燃燃料时所带来的经济性问题。同时旋风筒中的煤粉颗粒只需简单的破碎,与煤粉炉相比,大大节约了制粉电耗和复杂制粉系统所带来的高额成本。3. In the utility model, the reburning fuel contains a large amount of reducing combustible gas, which not only ensures the reduction efficiency of NO x in the reduction zone, but also makes it easier to burn the remaining fuel in the burnout zone. Most importantly, this This method solves the economic problems caused by obtaining reburning fuels such as ultra-fine coal and natural gas in conventional fuel reburning technology. At the same time, the pulverized coal particles in the cyclone only need to be simply crushed. Compared with the pulverized coal furnace, it greatly saves the high cost of pulverizing power consumption and complex pulverizing system.

4、煤粉在再燃旋风筒或旋风气化炉中的燃烧产物含有大量CO、碳氢化合物等具有还原性的高温气体,相比传统再燃燃料的种类,不仅还原基团的还原效果得到了提升,同时也弥补了常规燃料再燃技术中还原区反应温度不足的缺陷。4. The combustion products of pulverized coal in the reburning cyclone or cyclone gasifier contain a large amount of reducing high-temperature gases such as CO and hydrocarbons. Compared with the types of traditional reburning fuels, not only the reduction effect of reducing groups has been improved At the same time, it also makes up for the defect of insufficient reaction temperature in the reduction zone in the conventional fuel reburning technology.

5、对于旋风燃烧锅炉,由于主燃料的燃烧是在旋风筒中进行,为锅炉的主炉膛节省了很多空间,从一定程度上解决了常规燃料再燃技术中还原区长度不足的问题,进一步提升了整个系统的脱硝效率。5. For the cyclone combustion boiler, since the combustion of the main fuel is carried out in the cyclone tube, it saves a lot of space for the main furnace of the boiler, solves the problem of insufficient length of the reduction zone in the conventional fuel reburning technology to a certain extent, and further improves the overall efficiency. The denitrification efficiency of the system.

综上所述,本实用新型通过采用旋风燃烧的方式,保证了燃料的着火和稳定燃烧。在常规燃料再燃技术的基础上,把部分燃料送入再燃旋风筒或旋风气化炉中进行半气化或完全气化反应,将产生的高温气态产物作为再燃燃料,保证了还原区内所需的反应温度和有效还原基团的数量。同时由于允许更深程度的燃料分级,使得还原区的还原性气氛得到了进一步的增强,提高了系统的脱硝效率,气态的再燃燃料也使得燃尽区的燃烧更加容易。主燃料的燃烧是在旋风筒中进行,因而为主炉膛的还原区节约了大量空间,解决了以往还原区长度不足的缺陷。此外,各级旋风筒中的煤粉颗粒只需简单的破碎,大大节约了制粉电耗和复杂制粉系统所带来的成本问题,具有系统简单、成本低廉、实施改造容易等优点。In summary, the utility model ensures the ignition and stable combustion of the fuel by adopting the cyclone combustion method. On the basis of conventional fuel reburning technology, part of the fuel is sent into the reburning cyclone or cyclone gasifier for semi-gasification or complete gasification reaction, and the high-temperature gaseous products produced are used as reburning fuel to ensure the required energy in the reduction zone. The reaction temperature and the number of effective reducing groups. At the same time, the reducing atmosphere in the reduction zone is further enhanced by allowing deeper fuel classification, which improves the denitrification efficiency of the system, and the gaseous reburning fuel also makes the combustion in the burnout zone easier. The combustion of the main fuel is carried out in the cyclone, so a lot of space is saved in the reduction zone of the main furnace, and the defect of insufficient length of the reduction zone in the past is solved. In addition, the pulverized coal particles in the cyclones at all levels only need to be simply crushed, which greatly saves the power consumption of pulverization and the cost caused by the complex pulverization system. It has the advantages of simple system, low cost, and easy implementation of transformation.

附图说明:Description of drawings:

图1是本实用新型电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统的示意图。Fig. 1 is a schematic diagram of the utility model power station boiler adopting cyclone classification to realize fuel reburning and denitrification system.

其中:1、主燃旋风筒;2、主炉膛;3、再燃旋风筒或旋风气化炉;4、再燃燃料喷口;5、燃尽风喷口;6、主燃料一次风喷口;7、主燃区二次切向风喷口;8、旋风筒凹形出口;9、液态排渣设备。Among them: 1. Main combustion cyclone; 2. Main furnace; 3. Reburning cyclone or cyclone gasifier; 4. Reburning fuel nozzle; 5. Burn-out air nozzle; 6. Main fuel primary air nozzle; 7. Main combustion Secondary tangential wind nozzle in the area; 8. Cyclone concave outlet; 9. Liquid slag discharge equipment.

具体实施方式:detailed description:

下面结合附图和具体实例对本实用新型做进一步详细说明:Below in conjunction with accompanying drawing and concrete example the utility model is described in further detail:

本实用新型电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统的结构示意图如图1所示。包括有主燃旋风筒1、主炉膛2、再燃旋风筒或旋风气化炉3、再燃燃料喷口4、燃尽风喷口5、主燃料一次风喷口6、主燃区二次切向风喷口7、旋风筒凹形出口8以及液态排渣设备9。The structure schematic diagram of the system for implementing fuel reburning and denitrification by adopting cyclone classification in the utility model power station boiler is shown in Fig. 1 . Including main combustion cyclone 1, main furnace 2, reburning cyclone or cyclone gasifier 3, reburning fuel nozzle 4, burn-out air nozzle 5, main fuel primary air nozzle 6, main combustion zone secondary tangential air nozzle 7 , cyclone concave outlet 8 and liquid slag discharge equipment 9.

其中主燃旋风筒1和主炉膛2通过旋风筒的凹形出口8无缝连接,主炉膛最下端布置有液态排渣设备9,在主燃区上方的再燃燃料喷口处布置有再燃旋风筒或旋风气化炉3,炉膛上方一定位置处布置有燃尽风喷口5。Among them, the main combustion cyclone 1 and the main furnace 2 are seamlessly connected through the concave outlet 8 of the cyclone, a liquid slagging device 9 is arranged at the bottom of the main furnace, and a reburning cyclone or a reburning fuel nozzle is arranged above the main combustion area. In the cyclone gasification furnace 3, an overburning air nozzle 5 is arranged at a certain position above the furnace.

采用本实用新型提供的电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统的实现步骤为:1)由主燃旋风筒的一次风进口送入的燃料气流,与旋风筒侧面送入的二次风强烈混合,在其中完成大部分燃料的燃烧,并生成含有一定浓度NOx的烟气;2)在炉膛主燃区上方一定位置的再燃燃料喷口处布置有再燃旋风筒或旋风气化炉,将剩余煤粉在其中的燃烧产物作为二次燃料从再燃燃料喷口喷入主炉膛,并与步骤1)生成的含NOx的烟气发生还原反应,从而将NOx还原为N2;3)将燃烧所需剩余空气通过布置在炉膛上端一定位置处的燃尽风(OFA)喷口送入炉膛,完成剩余燃料的燃烧。The implementation steps of the system for realizing fuel reburning and denitrification by adopting cyclone grading for power plant boilers provided by the utility model are as follows: 1) the fuel air flow sent in from the primary air inlet of the main combustion cyclone, and the secondary air sent in from the side of the cyclone; The wind is strongly mixed, and most of the fuel is burned in it, and flue gas containing a certain concentration of NOx is generated; 2) A reburning cyclone or cyclone gasifier is arranged at a reburning fuel nozzle at a certain position above the main combustion zone of the furnace, The combustion product of the remaining pulverized coal is injected into the main furnace from the reburning fuel nozzle as a secondary fuel, and undergoes a reduction reaction with the NOx -containing flue gas generated in step 1), thereby reducing NOx to N2 ; 3) The remaining air required for combustion is sent into the furnace through the overfired air (OFA) nozzle arranged at a certain position on the upper end of the furnace to complete the combustion of the remaining fuel.

其中步骤1)所述的主燃旋风筒中通入总燃料量的70%~85%,并且在过量空气系数α为0.7~0.95的还原性气氛下进行燃烧。相比常规的燃料再燃技术,再燃燃料份额有了一定程度的增大,同时主燃区的过量空气系数可进一步减小。这样在旋风筒内,不仅保证了主燃料良好、稳定的燃烧,而且也有效抑制了NOx的大量生成,同时适当增大的再燃燃料份额也使得在原有基础上再燃区的还原性气氛有了进一步的增强。Wherein the main combustion cyclone described in step 1) passes 70% to 85% of the total fuel, and burns under a reducing atmosphere with an excess air coefficient α of 0.7 to 0.95. Compared with the conventional fuel reburning technology, the proportion of reburning fuel has been increased to a certain extent, and the excess air coefficient in the main combustion zone can be further reduced. In this way, in the cyclone, it not only ensures the good and stable combustion of the main fuel, but also effectively suppresses the massive generation of NOx . At the same time, the proportion of reburning fuel is appropriately increased, which also makes the reducing atmosphere in the reburning zone on the original basis. Further enhancements.

步骤2)中所述的再燃燃料可来源于再燃旋风筒或旋风气化炉中的燃烧产物。其中对于再燃旋风筒,15%~30%的剩余燃料在过量空气系数α为0.6~0.85的强还原性气氛下燃烧,发生半气化反应,同时有效抑制了新NOx的生成;对于旋风气化炉,可通过加入空气或水蒸气作为气化剂使燃料在其中发生气化反应,二者的燃烧产物中均含有CO、碳氢化合物等具有还原性的高温气体,将其作为再燃燃料与主燃区烟气中的NOx发生还原反应时,不仅具有足够的还原性基团,同时也提供了还原反应所需的高温环境,使还原效率大大提升。The reburning fuel mentioned in step 2) can come from combustion products in the reburning cyclone or cyclone gasifier. Among them, for the reburning cyclone, 15% to 30% of the remaining fuel is burned in a strong reducing atmosphere with an excess air coefficient α of 0.6 to 0.85, a semi-gasification reaction occurs, and the generation of new NO x is effectively suppressed at the same time; for the cyclone gas Fuel can be gasified by adding air or water vapor as a gasification agent, and the combustion products of both contain reductive high-temperature gases such as CO and hydrocarbons, which can be used as reburning fuel and When the reduction reaction of NO x in the flue gas in the main combustion zone occurs, it not only has enough reducing groups, but also provides the high temperature environment required for the reduction reaction, which greatly improves the reduction efficiency.

步骤3)中燃尽区的过量空气系数α为1.05~1.2,同时由于再燃燃料主要为气体,使得此处的燃尽变的更加容易,进一步提升了整体燃料的燃烧效率。The excess air coefficient α in the burnout area in step 3) is 1.05-1.2, and since the reburning fuel is mainly gas, the burnout here becomes easier, further improving the overall fuel combustion efficiency.

该装置在应用时,携带主燃料的一次风与切向高压二次风混合,在炉膛下端的数个主燃旋风筒内形成强烈旋转的流场并在具有一定还原性的气氛下完成燃烧;生成的含有一定浓度NOx的烟气随后与再燃旋风筒或旋风气化炉供给的再燃燃料混合发生还原反应,形成再燃区,使得烟气中的NOx被还原成N2,达到锅炉整体脱硝的目的;最后再与燃尽风喷口送入的燃尽风混合,完成剩余燃料的燃烧。When the device is in use, the primary air carrying the main fuel is mixed with the tangential high-pressure secondary air to form a strongly rotating flow field in several main combustion cyclones at the lower end of the furnace and complete the combustion under a certain reducing atmosphere; The generated flue gas containing a certain concentration of NOx is then mixed with the reburning fuel supplied by the reburning cyclone or cyclone gasifier to undergo a reduction reaction to form a reburning zone, so that the NOx in the flue gas is reduced to N 2 to achieve the overall denitrification of the boiler The purpose; Finally, it is mixed with the overburned air sent from the overburned air nozzle to complete the combustion of the remaining fuel.

在具体实施过程中,首先由一次风携带70%~85%的主燃料从主燃旋风筒的一次风喷口6喷入,旋风筒前端侧面布置有切向进风的二次风喷口7,一次风和主燃料在二次风形成的强旋转流场中充分混合,并在过量空气系数α<1的还原性气氛中燃烧,生成含有一定浓度NOx的烟气,主燃区的过量空气系数α为0.7~0.95,不仅保证了主燃料良好、稳定的燃烧,同时也有效抑制了NOx的大量生成。主燃区上方一定位置处布置有再燃燃料喷口,再燃燃料由再燃旋风筒或旋风气化炉3内的燃烧产物提供,其中在再燃旋风筒内,剩余15%~30%的燃料在过量空气系数α为0.6~0.85的强还原性气氛下燃烧,发生半气化反应,同时有效抑制了新NOx的生成;或者在旋风气化炉中,通过加入空气或水蒸汽作为气化剂使燃料发生气化反应,反应产物中含有CO、碳氢化合物等大量具有还原性的高温气体,将这些气体产物作为再燃燃料喷入主炉膛,与主燃区的烟气混合,在还原性气氛下发生反应,气体再燃燃料提供了此处还原反应所需的还原基团和高温环境。同时由于再燃燃料份额的适度增大,使得还原区的还原性气氛进一步增强,烟气中含有的NOx将更有效的被还原为N2。由于主燃料的燃烧是在炉膛以外的旋风筒中进行,大大节省了炉膛的空间,相比于常规燃料再燃技术,本实用新型中炉膛还原区的长度会有较大的增长,更有效的保证了NOx的减排效果。在炉膛上端布置有燃尽风(OFA)喷口5,提供燃料燃烧所需剩余空气,燃尽区的过量空气系数α为1.05~1.2。同时由于再燃燃料成分主要为可燃气体,因此燃尽区剩余燃料的燃烧也变得更加容易。In the specific implementation process, first, 70% to 85% of the main fuel is carried by the primary wind and sprayed from the primary air nozzle 6 of the main combustion cyclone, and the side of the front end of the cyclone is arranged with a tangential air inlet secondary air nozzle 7. The wind and the main fuel are fully mixed in the strong swirling flow field formed by the secondary air, and burn in a reducing atmosphere with an excess air coefficient α<1 to generate flue gas with a certain concentration of NOx . The excess air coefficient of the main combustion zone α is 0.7-0.95, which not only ensures the good and stable combustion of the main fuel, but also effectively suppresses a large amount of NOx formation. A reburning fuel nozzle is arranged at a certain position above the main combustion zone, and the reburning fuel is provided by the combustion product in the reburning cyclone or cyclone gasifier 3, wherein in the reburning cyclone, the remaining 15% to 30% of the fuel is in excess air coefficient Combustion in a strong reducing atmosphere with α of 0.6 to 0.85, a semi-gasification reaction occurs, and the formation of new NO x is effectively suppressed; or in a cyclone gasifier, the fuel is generated by adding air or water vapor as a gasification agent Gasification reaction, the reaction products contain a large amount of reducing high-temperature gases such as CO and hydrocarbons, these gas products are injected into the main furnace as reburning fuel, mixed with the flue gas in the main combustion area, and react in a reducing atmosphere , the gaseous reburn fuel provides the reducing groups and high-temperature environment required for the reduction reaction here. At the same time, due to the moderate increase in the proportion of reburned fuel, the reducing atmosphere in the reducing zone is further enhanced, and the NO x contained in the flue gas will be more effectively reduced to N 2 . Since the combustion of the main fuel is carried out in the cyclone outside the furnace, the space of the furnace is greatly saved. Compared with the conventional fuel reburning technology, the length of the reduction zone of the furnace in the utility model will be greatly increased, which more effectively guarantees The effect of reducing NOx emissions. An overfire air (OFA) nozzle 5 is arranged at the upper end of the furnace to provide the remaining air required for fuel combustion, and the excess air coefficient α in the burnout zone is 1.05 to 1.2. At the same time, since the main component of the reburning fuel is combustible gas, the combustion of the remaining fuel in the burnout zone becomes easier.

以上内容是结合具体的优选实施方式对本实用新型所作的进一步详细说明,不能认定本实用新型的具体实施方式仅限于此,对于本实用新型所属技术领域的普通技术人员来说,在不脱离本实用新型构思的前提下,还可以做出若干简单的推演或替换,都应当视为属于本实用新型由所提交的权利要求书确定专利保护范围。The above content is a further detailed description of the utility model in conjunction with specific preferred embodiments. It cannot be determined that the specific embodiment of the utility model is limited to this. Under the premise of the new concept, some simple deduction or replacement can also be made, which should be regarded as belonging to the utility model and the patent protection scope is determined by the submitted claims.

Claims (3)

1.电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统,其特征在于:包括主燃旋风筒(1)、主炉膛(2)以及再燃旋风筒或旋风气化炉(3);其中,1. A system in which boilers in power plants use cyclone classification to achieve fuel reburning and denitrification, which is characterized in that it includes the main combustion cyclone (1), the main furnace (2) and the reburning cyclone or cyclone gasifier (3); among them, 主炉膛(2)自下而上依次分为主燃区、再燃区和燃尽区,在主炉膛(2)主燃区周向上布置有主燃旋风筒(1),主炉膛(2)再燃区的再燃燃料喷口(4)处布置有再燃旋风筒或旋风气化炉(3),主炉膛(2)燃尽区周向上布置有燃尽风喷口(5)。The main furnace (2) is divided into main combustion zone, reburning zone and burnout zone from bottom to top. A main combustion cyclone (1) is arranged on the circumference of the main combustion zone of the main furnace (2), and the main furnace (2) reburns A reburning cyclone or cyclone gasifier (3) is arranged at the reburning fuel nozzle (4) in the zone, and an overburning air nozzle (5) is arranged on the circumference of the burnout zone of the main furnace (2). 2.根据权利要求1所述的电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统,其特征在于:主炉膛(2)底部布置有渐缩状结构的液态排渣设备(9)。2. The system according to claim 1, which adopts cyclone classification to achieve fuel reburning and denitrification system, characterized in that: the bottom of the main furnace (2) is arranged with a liquid slag removal device (9) with a tapered structure. 3.根据权利要求1所述的电站锅炉采用旋风筒分级来实现燃料再燃脱硝的系统,其特征在于:主燃旋风筒(1)的一端设置有主燃料一次风喷口(6),另一端设置有旋风筒凹形出口(8)并与主炉膛相连通,主燃旋风筒(1)的周向上设置有主燃区二次切向风喷口(7)。3. The power plant boiler according to claim 1 adopts cyclone classification to realize fuel reburning and denitrification system, characterized in that: one end of the main combustion cyclone (1) is provided with a main fuel primary air nozzle (6), and the other end is provided with There is a cyclone concave outlet (8) and communicates with the main furnace, and the main combustion cyclone (1) is provided with a secondary tangential air nozzle (7) in the main combustion area on the circumference.
CN201620542244.7U 2016-06-06 2016-06-06 Station boiler uses cyclone cylinder classification to realize the system of fuel denitration by refueling Expired - Fee Related CN205746802U (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105910097A (en) * 2016-06-06 2016-08-31 西安交通大学 System and method for achieving fuel reburning denitration through whirlwind cylinder grading of power station boiler
CN107099336A (en) * 2017-05-03 2017-08-29 中国科学院力学研究所 Cement decomposing furnace high temperature tertiary air coal gasification fires NO_x Reduction by Effective system again

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105910097A (en) * 2016-06-06 2016-08-31 西安交通大学 System and method for achieving fuel reburning denitration through whirlwind cylinder grading of power station boiler
CN107099336A (en) * 2017-05-03 2017-08-29 中国科学院力学研究所 Cement decomposing furnace high temperature tertiary air coal gasification fires NO_x Reduction by Effective system again

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