With the emphasis on environmental protection and the increase in environmental protection, from September 2013 to the present, the country has successively issued the "State Council's Notice on Printing and Distributing the Air Pollution Prevention and Control Action Plan" The Low-Carbon Development Action Plan Notice and other laws and regulations, as well as the eighth meeting of the Standing Committee of the Twelfth National People ’s Congress on April 24, 2014, revised and passed the Environmental Protection Law of Effective January 1, 2015). These laws and regulations require the state to conduct environmental work assessments for governments and enterprises at all levels, as well as accountability for environmental performance, and require industries and enterprises to meet new environmental standards. For the steel industry, steel companies are facing a severe environmental situation. A series of new emission standards for the steel industry such as GB 286622012 "Steel Sintering and Pellet Industrial Air Pollutant Emission Standards" proposed by the state have been officially implemented on October 1, 2012. Compared with existing standards, the emission concentration limits Both are significantly tightened. If the emission limits of the new standards are followed, there is still a large gap between the existing environmental protection levels of iron and steel enterprises. According to the newly announced requirements on the limits of atmospheric pollutant emissions, the joint venture of 10 million tons of steel has invested about 1 billion yuan in environmental protection. Therefore, iron and steel enterprises fully implement the standardization and transformation, which is tight in time, heavy in tasks, and heavy in capital pressure. Especially in the case of a large-scale loss in the steel industry, the choice of environmental protection equipment and processes should be more cautious. Hodgepodge of sintering desulfurization technology Sintering flue gas desulfurization technology is divided into dry method, semi-dry method and wet method. The wet method mainly includes lime-gypsum method, ammonia-ammonium sulfate method, magnesium oxide method, double alkali method, ionic liquid method, etc. The dry method mainly includes circulating fluidized bed method, dense phase dry tower method, MEROS method, activated carbon adsorption method, The flue circulation method (NID), etc., the semi-dry method mainly includes the circulating fluidized bed method (CFB), rotary spray drying method (SDA), dense phase dry tower method, etc. The “Announcement on Announcement of the List of Key Air Pollution Emission Reduction Projects of National Coal-fired Unit Desulfurization and Denitrification Facilities†issued by the General Office of the Ministry of Environmental Protection on July 8, 2014 shows that there are 526 desulfurization facilities in the iron and steel industry, and The area is 87,000 square meters, including 311 sets of lime-gypsum wet method, 46 sets of double alkali method, 35 sets of circulating fluidized bed method, 32 sets of magnesium oxide method, 22 sets of rotary spray method, 41 sets of ammonia method, dense coherence 6 sets of methods and 33 sets of desulfurization facilities of other methods. See the attached table for technical and economic indicators of sintering production of key iron and steel enterprises. At present, about 80% of the existing sintered flue gas desulfurization devices in China use wet desulfurization technology, of which about 60% are lime-gypsum methods. In terms of overall effect, wet desulfurization technology is relatively superior to dry desulfurization technology (except activated carbon adsorption method). However, there is currently no optimal desulfurization method. Analyze the pros and cons of reasonable choices There are several standards for evaluating the level of sintering flue gas desulfurization technology equipment: high desulfurization efficiency (greater than 90%), high equipment operation rate (greater than 90%), by-products can be recycled, long equipment life, price (investment, operation And maintenance) Low and stable and excellent performance of process technology. Lime-gypsum method. The method has mature technology and high desulfurization efficiency (more than 90%), but it has the problems of corroding equipment and serious scaling, and the chimney rain is serious. Controlling the PH value in the absorption tower is the key to this desulfurization technology, which will affect the desulfurization efficiency, equipment life, operating cost and by-product quality. The amount of flue gas, SO2 concentration and temperature of the sintering machine using this desulfurization technology are constantly changing, making it difficult to control. As a result, the sintering opportunity has operating fluctuations. At the same time, due to the low exhaust temperature, it has a great impact on the surrounding environment, the by-product gypsum is difficult to dehydrate, and contains high impurities (heavy metals, dioxins, etc.), making it difficult to optimize the use. The sintered flue gas of Hebei Iron & Steel Group Tanggang has a low sulfur content of 800mg / m3 ～ 1200mg / m3, and the exhaust gas of lime-gypsum method is 100mg / m3. The SO2 content of sintered flue gas of Pangang is 6000mg / m3 ～ 8000mg / m3, it is difficult to achieve an emission standard of less than 200mg / m3 using the lime-gypsum method. Circulating fluidized bed method. The technology is mature (in the absorption tower, the mixture of circulating ash and absorbent forms a fluidized bed, the gasification of water is a good condition for removing pollutants, the desulfurization efficiency is stable above 95%, and the synchronous operation rate is above 95%), The problem of paste bags can be solved by controlling the reaction temperature, the reaction speed is adjustable, the low-temperature desulfurization effect is good, and the investment and operating costs are low. However, its by-product utilization value is not high, and the denitration efficiency is not high. Meishan Iron & Steel 400m2 sintering machine invested 80 million yuan to apply this method. The desulfurization efficiency is 96.4%, the out-of-stock efficiency is 11.5%, the dust removal efficiency is 99.1%, the SO2 emission concentration is 50.76mg / m3, the NOx emission concentration is 184mg / m3, and the particulate matter The concentration is 6.12mg / m3, and the operating cost of sinter is 5.6 yuan / ton. Ammonia-ammonium sulfate method. The desulfurization technology is mature, the desulfurization efficiency reaches more than 90%, and the by-product is ammonium sulfate. The disadvantage of this technology is that there are serious problems such as equipment corrosion, ammonia escape and aerosol phenomena. The by-products of this technology are enriched in heavy metals and dioxins, and the production of chemical fertilizers will contaminate the soil and crops. The amount of chemical fertilizers (especially nitrogen fertilizers) applied in China is 35% of the world's consumption (three times that of the United States), which has a serious impact on the atmosphere and water quality. The excessive use of nitrogen fertilizer in agriculture in China has caused serious environmental pollution and should be brought to people's attention. At the same time, the market price of ammonium sulfate fluctuates greatly, and the economy will also be affected. Activated carbon adsorption method. The activated carbon adsorption method is an advanced and mature technology, which can achieve the effect of comprehensive treatment of flue gas, and can also remove SO2, SO3, NOx, dioxins, heavy metals and dust, etc. The disadvantages are high investment and operating costs, and energy consumption Also high. The method strictly controls the concentration and temperature of flue gas SO2, the system desulfurization efficiency is 80%, the denitration rate is 65%, the effluent SO2 concentration is less than 87mg / Nm3, the NOx concentration is less than 100mg / Nm3, and the dust concentration is less than 40mg / Nm3. The concentration of dioxin is less than 0.5ng-TEQ / Nm3, which meets the new national environmental protection standards. SHENZHEN 4IN1 ELECTRONIC TECHNOLOGY CO.LTD , https://www.siheyidz.com