技术领域technical field
本发明属于钢铁行业烟气脱硫脱硝及余热利用技术领域，具体涉及一种烧结烟气循环联合臭氧预氧化的脱硫脱硝系统及方法。The invention belongs to the technical field of flue gas desulfurization and denitrification and waste heat utilization in the iron and steel industry, and in particular relates to a desulfurization and denitrification system and method using sintering flue gas circulation combined with ozone pre-oxidation.
背景技术Background technique
钢铁行业属于高污染行业，铁矿石烧结过程中本身要产生大量烟气，另外由于国内烧结机漏风率高达40％以上，有相当一部分空气没有通过烧结料层，直接进入后续烟气处理装置，因此烧结烟气量非常巨大。比如一台360m2烧结机正常生产时，排放的烟气量高达每小时216万立方米以上。除了烧结烟气量大以外，还具有排放源集中、烟气温度波动大(随烧结工艺状况变化)，携带粉尘多、CO含量较高、SO2浓度较低、含湿量大、含腐蚀性气体及二噁英类物质等特点，因此对局部大气质量的影响较大，会造成严重的环境污染，因此很有必要对烧结烟气污染物进行净化，达到环保减排的效果。The iron and steel industry is a high-pollution industry. The iron ore sintering process itself produces a lot of smoke. In addition, because the air leakage rate of the domestic sintering machine is as high as 40%, a considerable part of the air does not pass through the sintering material layer and directly enters the subsequent flue gas treatment device. Therefore, the amount of sintering flue gas is very large. For example, when a 360m2 sintering machine is in normal production, the amount of flue gas emitted is as high as 2.16 million cubic meters per hour. In addition to the large amount of sintering flue gas, it also has concentrated emission sources, fluctuating flue gas temperature (changing with the sintering process), carrying a lot of dust, high CO content, low SO2 concentration, large moisture content, and corrosive The characteristics of gas and dioxin-like substances have a greater impact on local air quality and cause serious environmental pollution. Therefore, it is necessary to purify sintering flue gas pollutants to achieve the effect of environmental protection and emission reduction.
当前我国钢铁企业，大气污染物治理措施可大致总结为三大类：1.原料控制，烟气减排的基础条件；2.烧结过程控制，烟气减排的有效手段；3.烟气末端治理，烟气治理的终极手段与最终保障。在以上三种治理措施中，人们往往更关注烟气末端治理。目前，烧结烟气末端治理主要有活性焦脱硫脱硝一体化、烟气脱硫(湿法、干法、半干法)+中低温SCR脱硝一体化等技术。SCR(Selective Catalytic Reduction)为选择性催化还原技术，其中中低温SCR技术脱硝原理为：在催化剂作用下，向温度约220～280℃的烟气中喷入还原剂氨，将NOx还原成N2和H2O。At present, my country's iron and steel enterprises, air pollutant control measures can be roughly summarized into three categories: 1. Raw material control, basic conditions for flue gas emission reduction; 2. Sintering process control, effective means for flue gas emission reduction; 3. Flue gas end Governance, the ultimate means and ultimate guarantee of flue gas treatment. Among the above three control measures, people tend to pay more attention to the treatment of the end of flue gas. At present, the terminal treatment of sintering flue gas mainly includes the integration of activated coke desulfurization and denitrification, flue gas desulfurization (wet method, dry method, semi-dry method) + medium and low temperature SCR denitration integration and other technologies. SCR (Selective Catalytic Reduction) is a selective catalytic reduction technology. The denitrification principle of the medium and low temperature SCR technology is: under the action of a catalyst, the reducing agent ammonia is sprayed into the flue gas at a temperature of about 220-280 ° C to reduce NOx to N2 andH2O .
活性焦脱硫脱硝一体化技术，主要存在着投资巨大、活性焦损耗大、运行成本高，工艺复杂，烟气通过吸附床后压力降低，增加能耗，喷射氨过程中造成管道堵塞、脱硫速率慢等缺点。The integrated technology of activated coke desulfurization and denitrification mainly has huge investment, large loss of active coke, high operating cost, complicated process, pressure drop after flue gas passes through the adsorption bed, increased energy consumption, pipeline blockage and slow desulfurization rate during the ammonia injection process and other shortcomings.
烟气脱硫+中低温SCR脱硝一体化技术也存在着诸多缺陷：1)存在温度窗口，反应温度在220℃以上，低于该温度时，烟气中的SO2会与NH3反应生成易腐蚀和堵塞设备的硫酸氨、硫酸氢氨，同时还会粘附在催化剂表面，导致催化剂的堵塞、硫中毒等，同时降低氨的利用率；2)催化剂消耗量大，寿命短投资成本高；3)废弃催化剂作为固体危废，处理成本高、难度大；4)烟气量大，导致烟气升温所需燃料消耗量大；5)脱硝效率已接近限值。Flue gas desulfurization + medium and low temperature SCR denitrification integrated technology also has many defects: 1) There is a temperature window, the reaction temperature is above 220 ° C, below this temperature, SO2 in the flue gas will react with NH3 to form corrosive Ammonium sulfate and ammonium bisulfate that block the equipment will also adhere to the surface of the catalyst, causing catalyst blockage, sulfur poisoning, etc., and reducing the utilization rate of ammonia; 2) Catalyst consumption is large, life is short and investment cost is high; 3 ) The waste catalyst is a solid hazardous waste, and the treatment cost is high and difficult; 4) The amount of flue gas is large, which leads to a large amount of fuel consumption required to raise the temperature of the flue gas; 5) The denitrification efficiency is close to the limit.
随着《钢铁烧结、球团工业大气污染物排放标准》(GB 28662-2012)修改单等国家和地方标准的不断出台，钢铁行业烟气污染物排放限值愈来愈低，末端脱硫/脱硝治理技术只能通过不断提高装置规模，增加吸收剂、催化剂等物料用量来达到排放限值，但于此同时，会出现企业投资运行压力增大、氨逃逸增加等一系列问题。With the continuous promulgation of national and local standards such as "Emission Standards of Air Pollutants for Iron and Steel Sintering and Pelletizing Industry" (GB 28662-2012), the emission limits of flue gas pollutants in the iron and steel industry are getting lower and lower, and terminal desulfurization/denitrification Treatment technology can only reach the emission limit by continuously increasing the scale of the device and increasing the amount of materials such as absorbents and catalysts. However, at the same time, there will be a series of problems such as increased investment and operating pressure for enterprises, and increased ammonia escape.
因此，需要提供一种不仅仅局限于烟气末端治理，而着眼于烧结烟气全流程治理的改进技术方案。Therefore, it is necessary to provide an improved technical solution that is not limited to the treatment of the end of the flue gas, but focuses on the whole process treatment of the sintering flue gas.
发明内容Contents of the invention
本发明的目的在于提供一种烧结烟气循环联合臭氧预氧化的脱硫脱硝系统及方法，以至少解决目前的烟气脱硫脱硝过程中的催化剂消耗量大，使用寿命短；烟气处理量大，导致消耗大量燃料用于烟气升温，从而提高了脱硫脱硝装置投资及运行成本；此外脱硝效果很难达到超低排放标准的问题。The object of the present invention is to provide a desulfurization and denitrification system and method combined with ozone pre-oxidation of sintering flue gas circulation, to at least solve the problem of large catalyst consumption and short service life in the current flue gas desulfurization and denitrification process; large flue gas treatment capacity, It leads to the consumption of a large amount of fuel for flue gas heating, thereby increasing the investment and operating costs of desulfurization and denitrification devices; in addition, it is difficult for the denitrification effect to meet the ultra-low emission standard.
为了实现上述目的，本发明提供如下技术方案：In order to achieve the above object, the present invention provides the following technical solutions:
一种烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，所述系统包括：设置在烧结机主烟道上的脱硫反应装置和脱硝反应装置，以及臭氧制备装置，其中：A desulfurization and denitrification system with sintering flue gas circulation combined with ozone pre-oxidation, the system includes: a desulfurization reaction device and a denitration reaction device arranged on the main flue of the sintering machine, and an ozone preparation device, wherein:
所述臭氧制备装置用于制备臭氧，所述臭氧用于对所述烧结机主烟道内进入所述脱硫反应装置前的烟气进行第一次臭氧预氧化处理，以及对所述烧结机主烟道内进入脱硝反应装置前的烟气进行第二次臭氧预氧化处理；The ozone preparation device is used to prepare ozone, and the ozone is used to perform the first ozone pre-oxidation treatment on the flue gas in the main flue of the sintering machine before entering the desulfurization reaction device, and to perform the first ozone pre-oxidation treatment on the main flue gas of the sintering machine. The flue gas in the duct before entering the denitrification reaction device is subjected to the second ozone pre-oxidation treatment;
经过所述第一次臭氧预氧化后的烟气进入所述脱硫反应装置，所述脱硫反应装置用于对烟气进行脱硫处理和第一次脱硝处理；The flue gas after the first ozone pre-oxidation enters the desulfurization reaction device, and the desulfurization reaction device is used to perform desulfurization treatment and first denitrification treatment on the flue gas;
来自所述脱硫反应装置的烟气经过所述第二次臭氧预氧化后进入所述脱硝反应装置，所述脱硝反应装置用于对烟气进行第二次脱硝处理。The flue gas from the desulfurization reaction device enters the denitration reaction device after the second ozone pre-oxidation, and the denitration reaction device is used to perform a second denitration treatment on the flue gas.
在如上所述的烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，优选，所述系统还包括烧结烟气循环装置，所述烧结烟气循环装置包括循环烟道，所述循环烟道与烧结设备形成回路；In the above-mentioned sintering flue gas circulation combined with ozone pre-oxidation desulfurization and denitrification system, preferably, the system also includes a sintering flue gas circulation device, the sintering flue gas circulation device includes a circulation flue, and the circulation flue is connected to the sintering flue The equipment forms a loop;
优选地，所述循环烟道的一端与烧结机风箱连通，另一端与所述烧结机的料面连通；更优选地，所述循环烟道的一端与所述烧结机的中前段和后段风箱连通；Preferably, one end of the circulating flue communicates with the wind box of the sintering machine, and the other end communicates with the material surface of the sintering machine; more preferably, one end of the circulating flue communicates with the front and rear sections of the sintering machine Bellows connection;
所述烧结烟气循环装置沿所述循环烟道中烟气流动方向依次设置第一除尘器、第一风机和氧气补给装置；所述氧气补给装置用于对所述循环烟道中的烟气提供氧气补给；优选地，所述第一除尘器为多管旋风除尘器。The sintering flue gas circulation device is sequentially provided with a first dust collector, a first fan and an oxygen supply device along the flow direction of the flue gas in the circulation flue; the oxygen supply device is used to provide oxygen to the flue gas in the circulation flue Replenishment; Preferably, the first dust collector is a multi-cyclone dust collector.
在如上所述的烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，优选，所述氧气补给装置包括连接在氧气缓冲罐出口的氧气均布器，从所述氧气均布器喷射出的氧气进入循环烟道。In the above-mentioned sintering flue gas circulation combined with ozone pre-oxidation desulfurization and denitrification system, preferably, the oxygen supply device includes an oxygen uniform distributor connected to the outlet of the oxygen buffer tank, and the oxygen injected from the oxygen uniform distributor enters the Circulation flue.
在如上所述的烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，优选，所述烧结烟气循环装置还包括多个密封罩，经过氧气补给后的烟气通过多个分支管道分别进入多个所述密封罩，所述密封罩与所述烧结机的料面连通，多个所述分支管道上均设有烟气调节阀，用于调节进入所述密封罩内的烟气；In the above-mentioned sintering flue gas circulation combined with ozone pre-oxidation desulfurization and denitrification system, preferably, the sintering flue gas circulation device also includes a plurality of sealing covers, and the flue gas after oxygen supply enters a plurality of branch pipes respectively. The sealing cover, the sealing cover is connected with the material surface of the sintering machine, and a plurality of branch pipes are provided with flue gas regulating valves for regulating the flue gas entering the sealing cover;
优选地，所述密封罩固定于所述烧结机中段料面上方，所述烧结机主烟道的一端至少与所述烧结机的机头及中段风箱连接，所述循环烟道内的烟气从所述密封罩进入所述烧结机中段并由所述中段风箱进入所述烧结机主烟道；Preferably, the sealing cover is fixed above the material surface of the middle section of the sintering machine, one end of the main flue of the sintering machine is at least connected to the head of the sintering machine and the wind box of the middle section, and the flue gas in the circulating flue flows from The sealing cover enters the middle section of the sintering machine and enters the main flue of the sintering machine from the middle bellows;
优选地，所述密封罩上设有压力表和氧气浓度分析仪，所述氧气浓度分析仪连接所述氧气补给装置，根据所述密封罩内氧气浓度自动控制氧气补给过程。Preferably, the sealed cover is provided with a pressure gauge and an oxygen concentration analyzer, the oxygen concentration analyzer is connected to the oxygen supply device, and the oxygen supply process is automatically controlled according to the oxygen concentration in the sealed cover.
在如上所述的烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，优选，所述臭氧制备装置制备的臭氧为与空气稀释混合后的臭氧；In the above-mentioned desulfurization and denitrification system of sintering flue gas circulation combined with ozone pre-oxidation, preferably, the ozone prepared by the ozone preparation device is ozone diluted and mixed with air;
优选地，所述臭氧经过第一管道传输并通过第一臭氧均布器喷射入烧结机主烟道，进行所述第一次臭氧预氧化处理；所述臭氧经过第二管道传输并通过第二臭氧均布器喷射入烧结机主烟道，进行所述第二次臭氧预氧化处理；Preferably, the ozone is transported through the first pipeline and sprayed into the main flue of the sintering machine through the first ozone uniform distributor to perform the first ozone pre-oxidation treatment; the ozone is transported through the second pipeline and passed through the second The ozone uniform distributor is injected into the main flue of the sintering machine to perform the second ozone pre-oxidation treatment;
所述第一臭氧均布器设置在所述烧结机主烟道的第一臭氧喷入部；所述第二臭氧均布器设置在所述烧结机主烟道的第二臭氧喷入部；The first ozone distributor is arranged at the first ozone injection part of the main flue of the sintering machine; the second ozone distributor is arranged at the second ozone injection part of the main flue of the sintering machine;
优选地，所述臭氧制备装置制备的臭氧中，纯臭氧与所述空气的体积比为(7-9)：1。Preferably, in the ozone produced by the ozone production device, the volume ratio of pure ozone to the air is (7-9):1.
在如上所述的烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，优选，所述烧结机主烟道上还设有第二除尘器，所述第二除尘器优选为机头电除尘器，所述机头电除尘器设于所述第一臭氧喷入部前方；In the above-mentioned sintering flue gas circulation combined with ozone pre-oxidation desulfurization and denitrification system, preferably, the main flue of the sintering machine is also provided with a second dust collector, and the second dust collector is preferably a machine head electric dust collector, so The head electrostatic precipitator is arranged in front of the first ozone injection part;
优选地，位于所述机头电除尘器前方的所述烧结机主烟道上设有第一NOx浓度分析仪；位于所述第二臭氧喷入部后方的所述烧结机主烟道上设有第二NOx浓度分析仪；在所述脱硝反应装置后的烧结机主烟道上设有第三NOx浓度分析仪和O3浓度分析仪；Preferably, a first NOx concentration analyzer is provided on the main flue of the sintering machine located in front of the electrostatic precipitator of the machine head; a second NOx concentration analyzer is installed on the main flue of the sintering machine behind the second ozone injection part. NOx concentration analyzer; the third NOx concentration analyzer andO3 concentration analyzer are arranged on the main flue of the sintering machine behind the denitrification reaction device;
优选地，所述系统还包括控制装置，至少与所述第一NOx浓度分析仪、所述第二NOx浓度分析仪、所述第三NOx浓度分析仪、所述O3浓度分析仪、第一臭氧喷入部和第二臭氧喷入部连接，以根据第一NOx浓度分析仪、第二NOx浓度分析仪、所述第三NOx浓度分析仪、所述O3浓度分析仪数据调节第一臭氧喷入部和第二臭氧喷入部的臭氧量。Preferably, the system further includes a control device, at least in communication with the first NOx concentration analyzer, the second NOx concentration analyzer, the third NOx concentration analyzer, theO3 concentration analyzer, the first The ozone injection part is connected with the second ozone injection part to adjust the first ozone injection part according to the data of the first NOx concentration analyzer, the second NOx concentration analyzer, the third NOx concentration analyzer, and theO3 concentration analyzer and the amount of ozone in the second ozone injection part.
在如上所述的烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，优选，所述脱硝反应装置后方的所述烧结机主烟道上设置有热回收装置；In the desulfurization and denitrification system with sintering flue gas circulation combined with ozone pre-oxidation as described above, preferably, a heat recovery device is arranged on the main flue of the sintering machine behind the denitrification reaction device;
优选地，所述热回收装置包括气体换热器和余热锅炉，沿烟气传输方向依次设置；更优选地，所述气体换热器与所述脱硝反应装置烟气入口处的所述烧结机主烟道连通且与所述脱硝反应装置出口处的所述烧结机主烟道连通；Preferably, the heat recovery device includes a gas heat exchanger and a waste heat boiler, which are arranged in sequence along the flue gas transmission direction; more preferably, the gas heat exchanger and the sintering machine at the flue gas inlet of the denitration reaction device The main flue is communicated with the main flue of the sintering machine at the outlet of the denitration reaction device;
优选地，所述脱硫反应装置为循环流化床脱硫反应器；所述脱硝反应装置为SCR反应装置。Preferably, the desulfurization reaction device is a circulating fluidized bed desulfurization reactor; the denitration reaction device is an SCR reaction device.
在如上所述的烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，优选，所述脱硝反应装置前的烧结机主烟道上沿烟气传输方向依次设有加热炉和氨喷射系统。In the desulfurization and denitrification system with sintering flue gas circulation combined with ozone pre-oxidation as described above, preferably, the main flue of the sintering machine in front of the denitrification reaction device is provided with a heating furnace and an ammonia injection system in sequence along the direction of flue gas transmission.
一种烧结烟气循环联合臭氧预氧化的脱硫脱硝方法，所述方法包括如下步骤：A desulfurization and denitrification method of sintering flue gas circulation combined with ozone pre-oxidation, said method comprising the following steps:
步骤一，臭氧预氧化处理的脱硫脱硝反应，包括：Step 1, the desulfurization and denitrification reaction of ozone pre-oxidation treatment, including:
烧结机主烟道的烟气经过第一次臭氧预氧化处理后进行脱硫处理和第一次脱硝处理，随后烟气经过第二次臭氧预氧化处理再进行第二次脱硝处理；The flue gas in the main flue of the sintering machine undergoes desulfurization treatment and first denitration treatment after the first ozone pre-oxidation treatment, and then the flue gas undergoes the second ozone pre-oxidation treatment and then the second denitrification treatment;
优选地，所述脱硫处理和第一次脱硝处理采用循环流化床脱硫反应器完成；所述第二次脱硝处理采用SCR反应装置完成；Preferably, the desulfurization treatment and the first denitration treatment are completed using a circulating fluidized bed desulfurization reactor; the second denitration treatment is completed using an SCR reaction device;
优选地，第二次臭氧预氧化处理后的烟气中NO与NO2的摩尔比为(0.95-1.05):1；Preferably, NO and NO in the flue gas after thesecond ozone pre-oxidation treatment The molar ratio is (0.95-1.05): 1;
步骤二，烟气外排，包括：Step 2, exhausting the flue gas, including:
经过所述第二次脱硝处理后的烟气经过降温后，从烟囱排放。The flue gas after the second denitration treatment is discharged from the chimney after being cooled.
在如上所述的烧结烟气循环联合臭氧预氧化的脱硫脱硝方法，优选，所述方法还包括烧结烟气循环步骤：In the desulfurization and denitrification method of sintering flue gas circulation combined with ozone pre-oxidation as described above, preferably, the method also includes the step of sintering flue gas circulation:
从烧结机风箱引出的烟气在循环烟道中与额外补给的氧气混合后进入烧结机中；优选地，该方法采用权利要求1-8任一项所述系统完成。The flue gas drawn from the wind box of the sintering machine enters the sintering machine after being mixed with additional supplementary oxygen in the circulating flue; preferably, the method is completed by using the system described in any one of claims 1-8.
与最接近的现有技术相比，本发明提供的技术方案具有如下优异效果：Compared with the closest prior art, the technical solution provided by the present invention has the following excellent effects:
1、本发明采用烧结烟气循环工艺，并在烟气循环过程中补入氧气，提高了烧结烟气循环率，烟气循环率提高至30％以上，同时能更大程度上降低外排烟气总量；在不改造烧结机台车情况下，提高成品矿的质量和产量；降低已投入运营的除尘、脱硫等污染物控制设施的运行费用；降低新建烧结机的污染物控制设施投资、运行成本。1. The present invention adopts the sintering flue gas circulation process, and supplements oxygen during the flue gas circulation process, which improves the sintering flue gas circulation rate, and the flue gas circulation rate is increased to more than 30%, and at the same time, the external smoke can be reduced to a greater extent increase the quality and output of finished ore without modifying the sintering machine trolley; reduce the operating costs of pollutant control facilities such as dust removal and desulfurization that have been put into operation; reduce the investment in pollutant control facilities for new sintering machines, Operating costs.
2、本发明采用的臭氧预氧化工艺，在脱硫反应装置前设有臭氧喷入点，臭氧将脱硫反应前的烟气中NO部分氧化为NO2、N2O5，高价态NOx在脱硫反应装置中被部分脱除，降低脱硝反应装置入口处NOx浓度；另外，对脱硝反应前的烟气也进行臭氧预氧化处理，控制烟气的NO/NO2摩尔比，实现在SCR反应器中发生快速脱硝反应，提高脱硝反应速率，减少催化剂用量，延长催化剂使用寿命，使NOx排放达到甚至超过烟气超低排放目标。2. The ozone pre-oxidation process adopted in the present invention is equipped with an ozone injection point before the desulfurization reaction device, and the ozone partly oxidizes NO in the flue gas before the desulfurization reaction to NO2 , N2 O5 , and the high-valence NOx is in the desulfurization reaction. The NOx concentration at the inlet of the denitrification reaction device is reduced; in addition, the flue gas before the denitrification reaction is also subjected to ozone pre- oxidation treatment, and the NO/NO2 molar ratio of the flue gas is controlled to realize the occurrence of NOx in the SCR reactor. Rapid denitrification reaction, increase the rate of denitrification reaction, reduce the amount of catalyst, prolong the service life of the catalyst, so that NOx emissions can reach or even exceed the target of ultra-low emission of flue gas.
附图说明Description of drawings
构成本申请的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。其中：The accompanying drawings constituting a part of the present application are used to provide a further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. in:
图1为本发明实施例的烧结烟气循环联合臭氧预氧化的脱硫脱硝系统流程图。Fig. 1 is a flowchart of a desulfurization and denitrification system with sintering flue gas circulation combined with ozone pre-oxidation according to an embodiment of the present invention.
图中：1、烧结机；2、多管旋风除尘器；3、第一风机；4、氧气缓冲罐；5、氧气均布器；6、调节阀；7、氧气浓度分析仪；8、压力表；9、密封罩；10、第一NOx浓度分析仪；11、机头电除尘器；12、第一臭氧均布器；13、脱硫反应装置；14、气体混合器；15、臭氧发生装置；16、第二臭氧均布器；17、第二NOx浓度分析仪；18、气体换热器；19、加热炉；20、氨喷射系统；21、脱硝反应装置；22、余热锅炉；23、第二风机；24、第三NOx浓度分析仪；25、第三风机；26、烟囱；27、循环烟道；28、烧结机主烟道；29、稀释风机；30、第一管道；31、第二管道；32、O3浓度分析仪。In the figure: 1. Sintering machine; 2. Multi-tube cyclone dust collector; 3. The first fan; 4. Oxygen buffer tank; 5. Oxygen uniform distributor; 6. Regulating valve; 7. Oxygen concentration analyzer; 8. Pressure Table; 9. Sealed cover; 10. The first NOx concentration analyzer; 11. Electrostatic precipitator at the machine head; 12. The first ozone uniform distributor; 13. Desulfurization reaction device; 14. Gas mixer; 15. Ozone generator 16, the second ozone uniform distributor; 17, the second NOx concentration analyzer; 18, gas heat exchanger; 19, heating furnace; 20, ammonia injection system; 21, denitrification reaction device; 22, waste heat boiler; 23, 24. The third NOx concentration analyzer; 25. The third fan; 26. The chimney; 27. The circulating flue; 28. The sintering machine main flue; 29. The dilution fan; 30. The first pipeline; 31. Second pipeline; 32, O3 concentration analyzer.
具体实施方式Detailed ways
下面将参考附图并结合实施例来详细说明本发明。需要说明的是，在不冲突的情况下，本发明中的实施例及实施例中的特征可以相互组合。The present invention will be described in detail below with reference to the accompanying drawings and examples. It should be noted that, in the case of no conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.
在本发明的描述中，术语“纵向”、“横向”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明而不是要求本发明必须以特定的方位构造和操作，因此不能理解为对本发明的限制。本发明中使用的术语“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接；可以是直接相连，也可以通过中间部件间接相连，可以是电路连接，也可以是通信连接，对于本领域的普通技术人员而言，可以根据具体情况理解上述术语的具体含义。In the description of the present invention, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", " The orientations or positional relationships indicated by "top", "bottom", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation, so they cannot be understood as Limitations on the Invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component, it can be a circuit connection, It can also be a communication connection, and those skilled in the art can understand the specific meanings of the above terms according to specific situations.
烧结料在烧结机1烧结过程中，烧结机1烟气热量分布不均，其中烧结机1头部风箱(即前段)烟气温度偏低，一般在150℃以下，烧结机风箱中后段的温度逐渐升高，温度可达300-450℃左右，机尾烟气温度较高，但烧结机各风箱烟气总热量是守恒的。同时烧结机1烟气污染物SO2、NOx、CO等污染物的浓度呈现出不同风箱的烟气存在不同排放特征的情况。During the sintering process of the sintering material in the sintering machine 1, the heat distribution of the flue gas of the sintering machine 1 is uneven, and the temperature of the flue gas at the head bellows of the sintering machine 1 (that is, the front section) is relatively low, generally below 150°C, and the temperature of the flue gas in the middle and rear sections of the sintering machine bellows is relatively low. The temperature rises gradually, and the temperature can reach about 300-450°C. The temperature of the flue gas at the tail of the machine is relatively high, but the total heat of the flue gas from each bellows of the sintering machine is conserved. At the same time, the concentration of SO2 , NOx, CO and other pollutants in the flue gas of sintering machine 1 presents the situation that the flue gas of different bellows has different emission characteristics.
若只将烧结机1后段风箱高温烟气引入循环烟道27，会使循环烟道27中烟气温度非常高，可高达300℃左右，有利于烧结烟气循环过程；但由于风箱烟气热量守恒，将必然导致烧结机主烟道28中烟气温度低于120℃，降至酸露点以下，导致烟道腐蚀、机头电除尘器11无法正常使用，并且会使加热炉19燃料消耗量巨大。If only the high-temperature flue gas from the bellows at the back section of the sintering machine 1 is introduced into the circulating flue 27, the temperature of the flue gas in the circulating flue 27 will be very high, up to about 300°C, which is beneficial to the circulation process of the sintering flue gas; Conservation of heat will inevitably lead to the temperature of the flue gas in the main flue 28 of the sintering machine being lower than 120°C, falling below the acid dew point, resulting in corrosion of the flue, failure of the head electrostatic precipitator 11, and fuel consumption of the heating furnace 19 Huge amount.
若只将烧结机1中前段风箱低温烟气引入循环烟道27，会使循环烟道27中烟气温度非常低，预计在100℃以下，不利于烧结烟气循环过程，且由于烟气低于酸露点，会导致烟道腐蚀、多管旋风除尘器2、第一风机3无法正常使用；由于风箱烟气热量守恒，将必然导致烧结机主烟道28中烟气温度过大，可达300℃以上，必然导致第一风机3烟气量、电耗剧增，风机、电机均无法满足负荷要求。If only the low-temperature flue gas from the wind box in the front section of the sintering machine 1 is introduced into the circulating flue 27, the temperature of the flue gas in the circulating flue 27 will be very low, which is expected to be below 100°C, which is not conducive to the sintering flue gas circulation process, and because the flue gas is low If the acid dew point is lower than the acid dew point, it will cause corrosion of the flue, and the multi-pipe cyclone dust collector 2 and the first fan 3 cannot be used normally; due to the heat conservation of the flue gas from the bellows, it will inevitably lead to excessive flue gas temperature in the main flue 28 of the sintering machine, which can reach Above 300°C, it will inevitably lead to a sharp increase in the flue gas volume and power consumption of the first fan 3, and neither the fan nor the motor can meet the load requirements.
综上，需要将烧结机中前段低温烟气与尾部(即后段)风箱高温烟气搭配进入循环烟道27，其余烟气进入烧结机主烟道28内，烧结机主烟道28内混合烟气温度在140-160℃，进入后续烟气净化系统。To sum up, it is necessary to combine the low-temperature flue gas in the front section of the sintering machine with the high-temperature flue gas from the tail (i.e., the rear section) bellows into the circulating flue 27, and the rest of the flue gas enters the main flue 28 of the sintering machine, and mixes in the main flue 28 of the sintering machine The flue gas temperature is 140-160°C and enters the subsequent flue gas purification system.
本发明中的“前”和“后”为基于烟气传输的方向所示的位置关系。"Front" and "rear" in the present invention are positional relationships based on the direction of smoke transmission.
如图1所示，根据本发明的实施例，提供了一种烧结烟气循环联合臭氧预氧化的脱硫脱硝系统，包括：As shown in Figure 1, according to an embodiment of the present invention, a desulfurization and denitrification system with sintering flue gas circulation combined with ozone pre-oxidation is provided, including:
烧结烟气循环装置，利用烧结烟气循环装置，对烧结机1中风箱烟气进行余热循环合理利用，保证在不影响烧结生产的前提下，最大化的利用烧结烟气余热。烧结烟气循环装置包括循环烟道27，循环烟道27与烧结机1形成回路，一端与烧结机1的风箱连通，另一端与烧结机1的料面连通；优选地，为了使整个系统正常运行且保证较高的烟气循环率，循环烟道27的一端与烧结机1的中前段和后段风箱连通，其余风箱与烧结机主烟道28连通，循环烟道27上设置有氧气补给装置，氧气补给装置用于对循环烟气提供氧气补给，氧气补给装置包括氧气缓冲罐4和连接在氧气缓冲罐4出口的氧气均布器5，从氧气均布器5喷射出的氧气进入循环烟道27对循环烟气进行补充氧气。氧气均布器5能够使得氧气的喷射与烟气混合的更均匀。根据烧结机1风箱烟气排放特征的差异，在不影响烧结矿质量的前提下，选择特定的风箱段烟气通过循环烟道27循环回烧结机1台车表面，用于热风烧结；在本发明的实施例中，共计风箱为23个的情况下，选取烧结机风箱编号为4#-8#和20#-23#的风箱内烟气进入循环烟道27，其余风箱中烟气进入烧结机主烟道28。The sintering flue gas circulation device uses the sintering flue gas circulation device to make reasonable use of the waste heat of the wind box flue gas in the sintering machine 1, so as to ensure the maximum utilization of the waste heat of the sintering flue gas without affecting the sintering production. The sintering flue gas circulation device includes a circulating flue 27, which forms a loop with the sintering machine 1, one end communicates with the wind box of the sintering machine 1, and the other end communicates with the material surface of the sintering machine 1; preferably, in order to make the whole system work normally running and ensuring a high flue gas circulation rate, one end of the circulating flue 27 is connected to the front and rear wind boxes of the sintering machine 1, and the remaining bellows are connected to the main flue 28 of the sintering machine, and the circulating flue 27 is provided with an oxygen supply The oxygen supply device is used to provide oxygen supply to the circulating flue gas. The oxygen supply device includes an oxygen buffer tank 4 and an oxygen uniform distributor 5 connected to the outlet of the oxygen buffer tank 4. The oxygen injected from the oxygen uniform distributor 5 enters the circulation The flue 27 supplements the circulating flue gas with oxygen. The oxygen homogenizer 5 can make the injection of oxygen and the flue gas mix more uniformly. According to the difference in the flue gas emission characteristics of the sintering machine 1 bellows, under the premise of not affecting the quality of sinter, the flue gas of a specific bellows section is selected to circulate back to the surface of the sintering machine 1 trolley through the circulating flue 27 for hot air sintering; In the embodiment of the invention, when there are 23 bellows in total, the flue gas in the bellows of the sintering machine with numbers 4#-8# and 20#-23# enters the circulating flue 27, and the flue gas in the remaining bellows enters the sintering Machine main flue 28.
烧结烟气循环装置还包括密封罩9，经过氧气补给后的烧结循环烟气通过多个分支管道分别进入多个密封罩9，密封罩9内烟气连通烧结机1，密封罩9固定于所述烧结机1中段料面上方，以便于循环烟道的烟气从密封罩9进入烧结机中段料面，并由此向下进入中段风箱，然后再进入与中段风箱连接的烧结机主烟道28，本发明的具体实施例中，密封罩9固定的位置为与风箱9#-19#对应的料面层上方，循环烟气通过密封罩9进入烧结机1后从风箱9#-19#引出并进入烧结机主烟道28，以便经过氧气补给后的烟气循环一次即进入后续烟气净化系统，避免烟气多次循环导致烟气中污染物(SO2、NOx、颗粒物)富集。多个分支管道上均设有烟气调节阀6，用于调节进入密封罩9内的烟气；本发明的具体实施例中，循环烟气由烧结机1风箱引出后，经第一除尘器(优选为多管旋风除尘器2)、第一风机3后，分四路即四个分支管道，引入密封罩9，当然，根据烟气情况也可以设置其他数量的分支管道，本发明对此不做限定；密封罩9内的烟气在第二风机23产生的负压下，被吸入烧结料层，参与二次烧结过程，烧结后的烟气进入烧结机主烟道28，排入烧结机主烟道28进入后续烟气净化系统。在四个分支管道上分别安装有四个烟气调节阀6，根据烧结机1不同区域料层透气性及需气量差异，调控调节阀6的开度，使烟气压力在密封罩9内保持稳定，并维持微负压状态，保持-100Pa—0Pa，防止烟气外泄。为保证实时监测烟气压力，在每个密封罩9上均设置有压力检测装置压力表8。The sintering flue gas circulation device also includes a sealing cover 9, and the sintering circulating flue gas after oxygen supply enters into a plurality of sealing covers 9 respectively through a plurality of branch pipes, and the flue gas in the sealing cover 9 communicates with the sintering machine 1, and the sealing cover 9 is fixed on the Above the material surface of the middle section of sintering machine 1, so that the flue gas of the circulating flue enters the material surface of the middle section of the sintering machine from the sealing cover 9, and then enters the middle bellows downwards, and then enters the main flue of the sintering machine connected with the middle bellows 28. In a specific embodiment of the present invention, the fixed position of the sealing cover 9 is above the material surface layer corresponding to the bellows 9#-19#, and the circulating flue gas enters the sintering machine 1 through the sealing cover 9 and then flows from the bellows 9#-19# Lead out and enter the main flue 28 of the sintering machine, so that the flue gas after oxygen supply can enter the subsequent flue gas purification system after one cycle, so as to avoid the enrichment of pollutants (SO2 , NOx, particulate matter) in the flue gas caused by multiple cycles of flue gas . A flue gas regulating valve 6 is provided on a plurality of branch pipes for regulating the flue gas entering the sealing cover 9; (preferably multi-pipe cyclone dust collector 2), after the first blower fan 3, divide four roads namely four branch pipes, introduce sealing cover 9, certainly, also can be provided with other number of branch pipes according to flue gas situation, the present invention to this It is not limited; the flue gas in the sealing cover 9 is sucked into the sintering layer under the negative pressure generated by the second fan 23, and participates in the secondary sintering process. The flue gas after sintering enters the main flue 28 of the sintering machine and is discharged into the sintering machine The main flue 28 enters the follow-up flue gas purification system. Four flue gas regulating valves 6 are respectively installed on the four branch pipes, and the opening of the regulating valves 6 is adjusted according to the difference in gas permeability and gas demand of the material layer in different areas of the sintering machine 1, so that the flue gas pressure is maintained in the sealing cover 9 Stable, and maintain a slight negative pressure state, maintain -100Pa-0Pa, to prevent the leakage of smoke. In order to ensure real-time monitoring of flue gas pressure, a pressure detection device pressure gauge 8 is provided on each sealing cover 9 .
优选地，密封罩9上设有氧气浓度分析仪7，氧气浓度分析仪7连接氧气补给装置，根据密封罩9内氧气浓度自动控制氧气补给过程，通过PID程序控制调节氧气补给量；保证经过氧气补给后的密封罩9中的烟气含氧量(氧气浓度)大于18％，当达到此含氧量时，不影响烧结生产。Preferably, an oxygen concentration analyzer 7 is provided on the sealing cover 9, and the oxygen concentration analyzer 7 is connected to an oxygen supply device, and the oxygen supply process is automatically controlled according to the oxygen concentration in the sealing cover 9, and the oxygen supply amount is controlled and regulated by a PID program; The oxygen content (oxygen concentration) of the flue gas in the sealed cover 9 after replenishment is greater than 18%, and when this oxygen content is reached, the sintering production will not be affected.
常规烧结烟气循环装置，可减少20％的外排烟气总量；本发明中选用纯氧气进行补氧，相比常规烧结烟气循环，可减少30％以上的外排烟气总量，能更大程度上降低烟气净化系统负荷。The conventional sintering flue gas circulation device can reduce the total amount of exhausted flue gas by 20%; in the present invention, pure oxygen is used for oxygen supplementation, which can reduce the total amount of exhausted flue gas by more than 30% compared with conventional sintering flue gas circulation. It can reduce the load of the flue gas purification system to a greater extent.
烧结机风箱内烟气可流向两个方向，一路是循环烟道27、另一路是烧结机主烟道28；循环烟道27的一端与烧结机中前段和后段的部分风箱分别连接，烧结机主烟道28的一端与烧结机全部风箱出口连接。在本发明的实施例中，对于同时与循环烟道27和烧结机主烟道28连接的风箱，可通过在连接某一风箱与循环烟道的主管路上设置与烧结机主烟道28连接的支管路，主管路和支管路上均设有烟气流量调控阀门，正常烧结循环情况下，前段和后段风箱中烟气进入循环烟道27参与一次循环后，循环后的烟气进入中段风箱接着进入烧结机主烟道28；而在设备维修或调试情况下，前段和后段风箱中烟气通过支管路上的烟气流量调控阀门的调控从支管路进入烧结机主烟道28，在主管路和支管路上的烟气流量调控阀门的控制下，烧结机内烟气可以向任意一路流动。The flue gas in the bellows of the sintering machine can flow in two directions, one is the circulating flue 27 and the other is the main flue 28 of the sintering machine; one end of the circulating flue 27 is respectively connected with the bellows of the front section and the rear section of the sintering machine, and the sintering One end of the machine main flue 28 is connected with all bellows outlets of the sintering machine. In the embodiment of the present invention, for the air box connected to the circulating flue 27 and the main flue 28 of the sintering machine at the same time, it can be connected to the main flue 28 of the sintering machine on the main line connecting a wind box and the circulating flue. The branch pipeline, the main pipeline and the branch pipeline are all equipped with flue gas flow control valves. Under normal sintering cycle conditions, the flue gas in the front and rear wind boxes enters the circulating flue 27 to participate in a cycle, and the recycled flue gas enters the middle wind box and then Enter the main flue 28 of the sintering machine; and in the case of equipment maintenance or debugging, the flue gas in the front and rear bellows enters the main flue 28 of the sintering machine from the branch pipeline through the control of the flue gas flow control valve on the branch pipeline, and enters the main flue 28 in the main pipeline. Under the control of the flue gas flow control valve on the branch pipeline, the flue gas in the sintering machine can flow in any direction.
在烧结机料面负压的作用下，烧结机料面上方的循环烟气被吸入料面，在烧结料层中发生复杂的物理、化学过程，包括CO的二次燃烧放热、二噁英的高温分解等，使污染物排放总量降低的同时，烟气显热全部供给烧结料，降低烧结过程中固体燃料消耗；此外，高温烟气在烧结料层上方对烧结料层均匀加热，能够改善表层烧结矿质量，提高烧结矿料层温度均匀性和破碎强度等理化指标，实现节能、减排、提产的多功能耦合。Under the action of negative pressure on the material surface of the sintering machine, the circulating flue gas above the material surface of the sintering machine is sucked into the material surface, and complex physical and chemical processes occur in the sintering material layer, including secondary combustion of CO, heat release of dioxin pyrolysis, etc., to reduce the total amount of pollutant emissions, and at the same time, all the sensible heat of the flue gas is supplied to the sintering material, reducing the consumption of solid fuel in the sintering process; in addition, the high-temperature flue gas heats the sintering material layer evenly above the sintering material layer, which can Improve the quality of surface sinter, improve physical and chemical indicators such as temperature uniformity and crushing strength of sinter material layer, and realize multi-functional coupling of energy saving, emission reduction and production increase.
臭氧制备装置，臭氧制备装置用于制备臭氧，分别对脱硫反应前的烟气进行第一次臭氧预氧化处理，和脱硝反应前的烟气进行第二次臭氧预氧化处理；臭氧制备装置制备的臭氧为与空气稀释混合后的臭氧；臭氧制备装置包括臭氧发生装置15，臭氧发生装置15用于制备高纯臭氧。Ozone preparation device. The ozone preparation device is used to prepare ozone. The first ozone pre-oxidation treatment is performed on the flue gas before the desulfurization reaction, and the second ozone pre-oxidation treatment is performed on the flue gas before the denitrification reaction; the ozone preparation device prepares Ozone is diluted and mixed with air; the ozone production device includes an ozone generator 15, and the ozone generator 15 is used to prepare high-purity ozone.
臭氧的具体制备过程为氧气进入臭氧发生装置15，制备的高纯臭氧与稀释风机29送入的空气在气体混合器14中进行混合，形成待用臭氧。优选地，臭氧与空气的体积比为(7-9)：1(比如7:1、7.2:1、7.4:1、7.6:1、7.8:1、8:1、8.2:1、8.5:1、8.7:1)。The specific preparation process of ozone is that oxygen enters the ozone generator 15, and the prepared high-purity ozone is mixed with the air sent in by the dilution blower 29 in the gas mixer 14 to form ozone for use. Preferably, the volume ratio of ozone to air is (7-9): 1 (such as 7:1, 7.2:1, 7.4:1, 7.6:1, 7.8:1, 8:1, 8.2:1, 8.5:1 , 8.7:1).
高纯臭氧气体对金属材料有很强的氧化性、腐蚀性，稀释臭氧的作用有两个：一是降低臭氧浓度，在一定程度上降低对金属烟道的影响；二是用空气稀释臭氧，增大混合气体体积，有利于喷入烟道后，与烟气均匀混合，从而有利于臭氧与烟气中NOx的化学反应。High-purity ozone gas has strong oxidizing and corrosive properties on metal materials. There are two effects of diluting ozone: one is to reduce the concentration of ozone and reduce the impact on the metal flue to a certain extent; the other is to dilute ozone with air, Increasing the volume of the mixed gas is beneficial to uniform mixing with the flue gas after being sprayed into the flue gas, thus facilitating the chemical reaction between ozone and NOx in the flue gas.
优选地，臭氧经过第一管道30传输并通过第一臭氧均布器12喷射入烧结机主烟道28，对脱硫反应前的烟气进行第一次臭氧预氧化处理；臭氧经过第二管道31传输并通过第二臭氧均布器16喷射入烧结机主烟道28，对脱硫反应后脱硝反应前的烟气进行第二次臭氧预氧化处理。第一臭氧均布器12设置在烧结机主烟道28的第一臭氧喷入部；第二臭氧均布器16设置在烧结机主烟道28的第二臭氧喷入部，臭氧均布器用于将臭氧均匀喷入烧结机主烟道28，与烟气混合均匀，反应充分。Preferably, ozone is transmitted through the first pipeline 30 and injected into the main flue 28 of the sintering machine through the first ozone uniform distributor 12, and the first ozone pre-oxidation treatment is performed on the flue gas before the desulfurization reaction; the ozone passes through the second pipeline 31 It is transmitted and sprayed into the main flue 28 of the sintering machine through the second ozone uniform distributor 16, and the second ozone pre-oxidation treatment is performed on the flue gas after the desulfurization reaction and before the denitrification reaction. The first ozone uniform distributor 12 is arranged on the first ozone injection part of the sintering machine main flue 28; the second ozone uniform distributor 16 is arranged on the second ozone injection part of the sintering machine main flue 28, and the ozone uniform distributor is used for The ozone is evenly sprayed into the main flue 28 of the sintering machine, mixed evenly with the flue gas, and fully reacted.
烧结机主烟道28上还设有第二除尘器，该除尘器可以为本领域常用除尘器，优选除尘效果达到99.5％以上，第二除尘器优选为机头电除尘器11，机头电除尘器11设于第一臭氧喷入部前方，除尘后的烟气再进行第一次臭氧预氧化处理。设置第一臭氧预氧化处理的作用是将进入脱硫反应装置13前的烟气中NO部分氧化为NO2、N2O5，高价态NOx在脱硫反应装置13中被部分脱除，降低脱硝反应装置21入口处NOx浓度，减轻脱硝反应装置21的脱硝压力，以便经过脱硝反应装置21处理后的烟气NOx浓度能够达到甚至超过烟气超低排放标准。The main flue 28 of the sintering machine is also provided with a second deduster, which can be a common deduster in this field, and the dedusting effect preferably reaches more than 99.5%. The second deduster is preferably the head electrostatic precipitator 11. The dust collector 11 is arranged in front of the first ozone injection part, and the flue gas after dust removal is subjected to the first ozone pre-oxidation treatment. The role of setting the first ozone pre-oxidation treatment is to partially oxidize NO in the flue gas before entering the desulfurization reaction device 13 into NO2 and N2 O5 , and high-valence NOx is partially removed in the desulfurization reaction device 13, reducing the denitrification reaction The NOx concentration at the entrance of the device 21 reduces the denitrification pressure of the denitrification reaction device 21, so that the NOx concentration of the flue gas treated by the denitrification reaction device 21 can reach or even exceed the ultra-low emission standard of flue gas.
优选地，位于机头电除尘器11前方的烧结机主烟道28上设有第一NOx浓度分析仪10，用于监测原烟气中NOx浓度数据。Preferably, a first NOx concentration analyzer 10 is provided on the main flue 28 of the sintering machine in front of the electrostatic precipitator 11 at the machine head to monitor the NOx concentration data in the raw flue gas.
脱硫反应装置13，经过第一次臭氧预氧化后的烟气进入脱硫反应装置13，对烟气进行脱硫处理，本发明的具体实施例中，脱硫反应装置13为循环流化床脱硫反应器，由于循环流化床脱硫反应器装置简单，运行过程中无废水产生，因此，非常适合作为烟气中高价态NOx的反应场所。当然在其他实施例中，脱硫反应装置13也可以是密相干塔、石灰石-石膏法、镁法等湿法或半干法脱硫方式，本发明对此不做限定；循环流化床脱硫装置可脱除一部分NOx，降低脱硝反应装置21即SCR反应装置入口NOx浓度，减轻脱硝反应装置21负荷。第一臭氧喷入部和脱硫反应装置13之间设置有第二风机23，用于将烧结机主烟道中烟气引入脱硫反应装置13。Desulfurization reaction device 13, the flue gas after the first ozone pre-oxidation enters the desulfurization reaction device 13, and the flue gas is desulfurized. In a specific embodiment of the present invention, the desulfurization reaction device 13 is a circulating fluidized bed desulfurization reactor. Since the circulating fluidized bed desulfurization reactor has simple equipment and no waste water is generated during operation, it is very suitable as a reaction site for high-valence NOx in flue gas. Of course, in other embodiments, the desulfurization reaction device 13 can also be a wet or semi-dry desulfurization method such as a dense phase dry tower, limestone-gypsum method, magnesium method, etc., which is not limited in the present invention; the circulating fluidized bed desulfurization device can be Remove a part of NOx, reduce the NOx concentration at the inlet of the denitration reaction device 21, that is, the SCR reaction device, and reduce the load of the denitration reaction device 21. A second fan 23 is provided between the first ozone injection part and the desulfurization reaction device 13 for introducing the flue gas in the main flue of the sintering machine into the desulfurization reaction device 13 .
在第一次臭氧预氧化处理时，控制O3:NO的摩尔比为3:2左右，能生成N2O5，有利于脱硫反应装置13中的第一次脱硝反应；N2O5非常容易被脱除，在脱硫反应装置13中大部分被吸收。During the first ozone pre-oxidation treatment, the molar ratio of O3 :NO is controlled to be about 3:2, which can generate N2 O5 , which is beneficial to the first denitrification reaction in the desulfurization reaction device 13; N2 O5 is very It is easy to be removed, and most of it is absorbed in the desulfurization reaction device 13.
臭氧氧化NO化学反应方程式：Ozone oxidation NO chemical reaction equation:
NO+O3→NO2+O2 (1)NO+O3 →NO2 +O2 (1)
2NO2+O3→N2O5+O2 (2)2NO2 +O3 →N2 O5 +O2 (2)
脱硫反应装置13中的第一次脱硝反应方程式：The first denitrification reaction equation in the desulfurization reaction device 13:
3NO2+H2O→2HNO3+NO3NO2 +H2 O→2HNO3 +NO
N2O5+H2O→2HNO3N2 O5 +H2 O→2HNO3
NO2+NO+H2O→2HNO2NO2 +NO+H2 O→2HNO2
Ca(OH)2+2HNO3→Ca(NO3)2+2H2OCa(OH)2 +2HNO3 →Ca(NO3 )2 +2H2 O
Ca(OH)2+2HNO2→Ca(NO2)2+2H2OCa(OH)2 +2HNO2 →Ca(NO2 )2 +2H2 O
脱硝反应装置21，经过脱硫反应后的烟气经过第二次臭氧预氧化后进入脱硝反应装置21，脱硝反应装置21用于对烟气进行第二次脱硝处理，烟气在脱硝反应装置21中发生SCR反应。位于脱硝反应装置21前的烧结机主烟道28上沿烟气流动方向依次设有加热炉19和氨喷射系统20，对烟气进行加热和喷氨处理，为进入脱硝反应装置21前的烟气做预处理。The denitrification reaction device 21, the flue gas after the desulfurization reaction enters the denitrification reaction device 21 after the second ozone pre-oxidation, and the denitrification reaction device 21 is used to perform the second denitrification treatment on the flue gas, and the flue gas is in the denitrification reaction device 21 An SCR reaction occurs. The main flue 28 of the sintering machine located in front of the denitrification reaction device 21 is provided with a heating furnace 19 and an ammonia injection system 20 in sequence along the flow direction of the flue gas. Gas for pretreatment.
本发明的具体实施例中，在加热炉19前设置第二臭氧喷入部，对烟气进行第二次臭氧预氧化处理的作用是从第二臭氧均布器16喷入的臭氧可以控制烟气中的NO/NO2摩尔比，NO/NO2摩尔比优选为0.95-1.05(比如0.96、0.97、0.98、0.99、1、1.01、1.02、1.03、1.04)，达到该比例的烟气进入脱硝反应装置21，发生快速SCR反应，相比标准SCR反应，能大大提高脱硝反应速率；快速SCR反应方程式：In a specific embodiment of the present invention, the second ozone injection part is set before the heating furnace 19, and the effect of the second ozone pre-oxidation treatment on the flue gas is that the ozone injected from the second ozone uniform distributor 16 can control the flue gasThe NO/NO2 molar ratio in the NO/NO2 molar ratio is preferably 0.95-1.05 (such as 0.96, 0.97, 0.98, 0.99,1 , 1.01, 1.02, 1.03, 1.04), and the flue gas that reaches this ratio enters the denitrification reaction The device 21 produces a fast SCR reaction, which can greatly increase the denitrification reaction rate compared with the standard SCR reaction; the fast SCR reaction equation:
2NH3+2NO2→NH3NO3+N2+H2O；2NH3 +2NO2 →NH3 NO3 +N2 +H2 O;
NH3NO3+NO→NO2+N2+2H2O；NH3 NO3 +NO→NO2 +N2 +2H2 O;
总反应：2NH3+NO2+NO→2N2+3H2O；Total reaction: 2NH3 +NO2 +NO→2N2 +3H2 O;
位于氨喷射系统20后方的烧结机主烟道28上设有第二NOx浓度分析仪17，用于监测经过第二次臭氧预氧化后的烟气中的NOx浓度。A second NOx concentration analyzer 17 is installed on the main flue 28 of the sintering machine behind the ammonia injection system 20 for monitoring the NOx concentration in the flue gas after the second ozone pre-oxidation.
当O3:NO摩尔比为1:1左右时，方程式(1)为主要反应，产物为NO2；当O3:NO摩尔比的比例为1:1～3:2左右时，方程式(1)(2)同时发生，产物为NO2和N2O5；由于N2O5在脱硫塔中大部分被吸收，因此，在脱硫反应装置13后，烟气中NOx主要为NO和NO2，通过控制第二次臭氧氧化中O3:NO的摩尔比为1:1左右，尽量少的生成N2O5，使进第二次脱硝处理前烟气中NO:NO2摩尔比为0.95-1.05，利于快速脱硝反应的进行。When the O3 :NO molar ratio is about 1:1, equation (1) is the main reaction, and the product is NO2 ; when the ratio of O3 :NO molar ratio is about 1:1～3:2, equation (1 )(2) occur simultaneously, and the products are NO2 and N2 O5 ; since most of N2 O5 is absorbed in the desulfurization tower, after the desulfurization reaction device 13, the NOx in the flue gas is mainly NO and NO2 , by controlling the molar ratio of O3 :NO in the second ozone oxidation to about 1:1, as little as possible to generate N2 O5 , so that the molar ratio of NO:NO2 in the flue gas before the second denitrification treatment is 0.95 -1.05, which is conducive to the rapid denitrification reaction.
为了充分节约热源，减少加热炉19煤气耗量，在脱硝反应装置21入口的加热炉19前设置一级热回收装置气体换热器18，气体换热器18位于脱硝反应装置21前、后的烧结机主烟道28上，将脱硝反应前的低温烟气与脱硝反应后的高温烟气进行热交换。另外，脱硝处理后的热烟气经过气体换热器18后，排出的烟气温度仍有200℃左右，因此在烧结机主烟道28上还设置有二级热回收装置余热锅炉22，余热锅炉22用于换热，产生蒸汽或热水，烟气温度降至170℃以下，经过第三风机25从烟囱26排放。In order to fully save the heat source and reduce the gas consumption of the heating furnace 19, a primary heat recovery device gas heat exchanger 18 is arranged in front of the heating furnace 19 at the entrance of the denitrification reaction device 21, and the gas heat exchanger 18 is located at the front and rear of the denitrification reaction device 21 On the main flue 28 of the sintering machine, the low-temperature flue gas before the denitrification reaction is exchanged with the high-temperature flue gas after the denitrification reaction. In addition, after the hot flue gas after denitrification treatment passes through the gas heat exchanger 18, the temperature of the discharged flue gas is still about 200°C. The boiler 22 is used for heat exchange to generate steam or hot water, the temperature of the flue gas drops below 170°C, and the flue gas is discharged from the chimney 26 through the third fan 25 .
从烧结机1排出的烟气，依次经过机头电除尘器11、第二风机23、脱硫反应装置13、气体换热器18、加热炉19、氨喷射系统20、脱硝反应装置21、气体换热器18、余热锅炉22、第三风机25，最后经烟囱26排放。The flue gas discharged from the sintering machine 1 passes through the head electrostatic precipitator 11, the second fan 23, the desulfurization reaction device 13, the gas heat exchanger 18, the heating furnace 19, the ammonia injection system 20, the denitrification reaction device 21, the gas exchange Heater 18, waste heat boiler 22, third blower fan 25, and finally discharge through chimney 26.
位于第三风机25后方的烧结机主烟道28上还设有第三NOx浓度分析仪24，对从烟囱26排放前的烟气检测其NOx浓度。A third NOx concentration analyzer 24 is also installed on the main flue 28 of the sintering machine behind the third fan 25 to detect theNOx concentration of the flue gas before being discharged from the chimney 26 .
根据检测原烟气的第一NOx浓度分析仪10、脱硝入口处的第二NOx浓度分析仪17和烟囱26入口前的第三NOx浓度分析仪24和O3浓度分析仪32的数据反馈，对第一臭氧喷入部和第二臭氧喷入部的臭氧喷入量进行PID自动控制调节。通过自动调节臭氧喷入量，设置的两个臭氧喷入点来调整SCR反应入口的NO/NO2摩尔比，使催化剂床层内尽可能多的发生快速SCR反应，从而提高脱硝反应速率、减少催化剂用量，延长催化剂使用寿命。According to the data feedback of the first NOx concentration analyzer 10 of detecting former flue gas, the second NOx concentration analyzer 17 at the denitrification inlet and the third NOx concentration analyzer 24 andO3 concentration analyzer 32 before the chimney 26 inlet, to The ozone injection amount of the first ozone injection part and the second ozone injection part is automatically controlled and adjusted by PID. By automatically adjusting the amount of ozone injection and settingtwo ozone injection points to adjust the molar ratio of NO/NO2 at the SCR reaction inlet, the rapid SCR reaction occurs as much as possible in the catalyst bed, thereby increasing the denitrification reaction rate and reducing Catalyst dosage, prolong catalyst service life.
为了进一步理解本发明的脱硫脱硝系统，本发明还提供了一种烧结烟气循环联合臭氧预氧化的脱硫脱硝方法，具体包括如下步骤：In order to further understand the desulfurization and denitrification system of the present invention, the present invention also provides a desulfurization and denitrification method of sintering flue gas circulation combined with ozone pre-oxidation, which specifically includes the following steps:
步骤一，烧结烟气循环Step 1, sintering flue gas circulation
从烧结机1特定风箱引出的烟气经过多管旋风除尘器2、第一风机3、氧气补给装置和密封罩9后重新循环进入烧结机1，补给后的密封罩9内烟气含氧量确保大于18％，用于热风烧结，烧结后的烟气通过烧结机主烟道28进入净化系统脱硫脱硝。The flue gas drawn from the specific bellows of the sintering machine 1 passes through the multi-pipe cyclone dust collector 2, the first fan 3, the oxygen supply device and the sealing cover 9, and then recirculates into the sintering machine 1. The oxygen content of the flue gas in the sealing cover 9 after supply is Ensure that it is greater than 18% for hot air sintering, and the flue gas after sintering enters the purification system for desulfurization and denitrification through the main flue 28 of the sintering machine.
步骤二，臭氧预氧化处理的脱硫脱硝反应Step 2, desulfurization and denitrification reaction of ozone pre-oxidation treatment
烧结机主烟道28的烟气依次经过机头电除尘器11、第一次臭氧预氧化处理和第二风机23后进入脱硫反应装置13，进行脱硫处理和第一次脱硝处理，并去除部分高价态NOX，随后烟气经过第二次臭氧预氧化处理、气体换热器18、加热炉19和氨喷射系统20后进入脱硝反应装置21，进行第二次脱硝处理，发生快速SCR脱硝反应。The flue gas from the main flue 28 of the sintering machine passes through the head electrostatic precipitator 11, the first ozone pre-oxidation treatment and the second blower 23 in sequence, and then enters the desulfurization reaction device 13 for desulfurization treatment and first denitrification treatment, and removes some High-valence state NOX , then the flue gas enters the denitration reaction device 21 after the second ozone pre-oxidation treatment, gas heat exchanger 18, heating furnace 19 and ammonia injection system 20, and performs the second denitration treatment, and a rapid SCR denitration reaction occurs .
步骤三，烟气外排Step 3, smoke exhaust
经过脱硝反应后的烟气再次经过气体换热器18和余热锅炉22的热回收，烟气温度降低，从烟囱26排放。The flue gas after the denitrification reaction passes through the heat recovery of the gas heat exchanger 18 and the waste heat boiler 22 again, the temperature of the flue gas is lowered, and the flue gas is discharged from the chimney 26 .
综上所述，本发明采用烧结烟气循环工艺联合臭氧预氧化处理的脱硫脱硝反应，在烧结烟气循环过程中补入纯氧气并可实现自动调节喷入量，提高了烧结烟气循环率，烟气循环率提高至30％以上，同时能更大程度上降低外排烟气总量；在不改造烧结机台车情况下，提高成品矿的质量和产量；降低已投入运营的除尘、脱硫等污染物控制设施的运行费用；降低新建烧结机的污染物控制设施投资、运行成本。In summary, the present invention adopts the desulfurization and denitrification reaction of sintering flue gas circulation process combined with ozone pre-oxidation treatment, supplements pure oxygen in the sintering flue gas circulation process and can automatically adjust the injection amount, and improves the sintering flue gas circulation rate , the flue gas circulation rate is increased to more than 30%, and at the same time, the total amount of exhausted flue gas can be reduced to a greater extent; the quality and output of finished ore can be improved without modifying the sintering machine trolley; the dust removal, The operating cost of pollutant control facilities such as desulfurization; reduce the investment and operating costs of pollutant control facilities for new sintering machines.
采用的臭氧预氧化工艺，在脱硫反应装置前设有臭氧喷入点，臭氧将脱硫反应前的烟气中NO部分氧化为NO2、N2O5，高价态NOx在脱硫反应装置中被部分脱除，降低脱硝反应装置入口处NOx浓度，减轻后续脱硝反应的负荷；另外，对脱硝反应前的烟气也进行臭氧预氧化处理，控制烟气的NO/NO2摩尔比，实现快速脱硝反应。本发明的脱硫脱硝系统和工艺减少了固体燃料消耗，提高了脱硝反应速率，减少催化剂用量，延长催化剂使用寿命，节约投资运行成本，通过两个脱硝反应场所，使NOx排放达到并超过超低排放目标。The ozone pre-oxidation process adopted is equipped with an ozone injection point in front of the desulfurization reaction device. The ozone partially oxidizes NO in the flue gas before the desulfurization reaction to NO2 and N2 O5 , and the high-valence NOx is partially eliminated in the desulfurization reaction device. Removal, reduce the NOx concentration at the entrance of the denitrification reaction device, and reduce the load of the subsequent denitrification reaction; in addition, the flue gas before the denitrification reaction is also subjected to ozone pre- oxidation treatment, and the NO/NO2 molar ratio of the flue gas is controlled to achieve rapid denitrification reaction . The desulfurization and denitrification system and process of the present invention reduce solid fuel consumption, increase the denitrification reaction rate, reduce catalyst consumption, prolong catalyst service life, save investment and operation costs, and make NOx emissions reach and exceed ultra-low emissions through two denitrification reaction sites Target.
以上所述仅为本发明的优选实施例，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
| Application Number | Priority Date | Filing Date | Title |
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| CN201910907254.4ACN110523251A (en) | 2019-09-24 | 2019-09-24 | A desulfurization and denitrification system and method for sintering flue gas circulation combined with ozone pre-oxidation |
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| CN201910907254.4ACN110523251A (en) | 2019-09-24 | 2019-09-24 | A desulfurization and denitrification system and method for sintering flue gas circulation combined with ozone pre-oxidation |
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| CN110523251Atrue CN110523251A (en) | 2019-12-03 |
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| CN201910907254.4APendingCN110523251A (en) | 2019-09-24 | 2019-09-24 | A desulfurization and denitrification system and method for sintering flue gas circulation combined with ozone pre-oxidation |
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| RJ01 | Rejection of invention patent application after publication | Application publication date:20191203 |