Review and Prospect of new technology application

Review and Prospect of the application of new technology of blast furnace hot blast stove in China in the past 20 years, with the rapid development of China's economy, the blast furnace ironmaking technology has made rapid progress. The large-scale, diversified and efficient blast furnace hot blast stove has greatly narrowed the gap between us and the world's advanced level. A large number of ironmaking and related scientific and technological workers have developed a series of world-class leading technologies with independent intellectual property rights, It fills the gap of hot blast stove technology at home and abroad and attracts the attention of the world. It is mainly manifested in: the introduction of hoghoven high-temperature hot blast stove, the combination of large-scale external combustion hot blast stove or large-scale external combustion hot blast stove plus auxiliary small hot blast stove, top combustion hot blast stove (the introduction of okalukin top combustion stove, the development of ball top combustion stove and reverse swirl top combustion stove), the successful application of self preheating type of large-scale external combustion hot blast stove in large blast furnaces Blast furnace hot blast stove flue gas waste heat preheating combustion supporting air and gas technology and its additional heating and heat exchange technology combination, etc. All these have achieved the actual effect of high wind temperature. System optimization of hot blast stove design, independent design and manufacture of different types of blast furnace hot blast stoves, and the combination bricks used at each intersection can be independently designed, manufactured and built. The research and development of blast furnace hot blast stove drying technology, furnace cooling and insulation technology, refractory materials and refractory coatings have greatly promoted the technical maturity and development of hot blast stove

has also made remarkable achievements in the theoretical research of blast furnace hot blast stove. For example, the application of computer technology, the development of numerical simulation technology, high-efficiency burners and cold and hot state experiments, cold air and flue gas distribution technology also have our own patents, and three theoretical and experimental studies on combustion, flow and heat transfer of blast furnace hot blast stove. The main technical routes to achieve high air temperature are: the process method of obtaining high air temperature by using low calorific value gas; Combination of thermal equipment; Optimization and innovation of process technology and materials; Some people in China also put forward the idea of 1400 ℃ ultra-high wind temperature

in 2005, the average blast temperature of blast furnaces in China's key large and medium-sized iron and steel enterprises was 1084 ℃, which was significantly increased, but 100~150 ℃ lower than the international advanced level. Meanwhile, the blast furnace gas emission rate is still 9.51%. This not only wastes a lot of secondary energy, but also seriously pollutes the atmospheric environment. With the doubling of the cost of ironmaking manufacturing accounted for by the consumption of ironmaking fuel, high air temperature is becoming more and more important for oxygen enriched coal injection to strengthen ironmaking, promote the progress of ironmaking technology, reduce costs and increase economic benefits

application of high temperature air combustion technology

the process methods of using low calorific value gas to obtain high air temperature mainly include: (1) blast furnace gas enrichment method; (2) Metal heat exchanger method; (3) Self preheating method; (4) Oxygen enriched combustion supporting method; (5) Hot air mixing method; (6) Auxiliary hot blast stove method, etc. Among them, the two most typical methods: metal heat exchanger method and hot blast stove self preheating method basically represent the new development trend of today's high temperature air combustion technology in using low calorific value gas to obtain high air temperature

1 the rise of high temperature air combustion technology in China

high temperature air combustion (HTAC) is a new technology in the field of fuel combustion successfully developed in the 1990s. HTAC includes two basic technical means: one is maximum sensible heat recovery (or limit recovery) of combustion products; Second, the fuel burns in a low oxygen atmosphere. The fuel burns in low oxygen air under high temperature and performance tests such as stretching, peeling, deformation, tearing, heat sealing, bonding, puncture force, opening force, low-speed unwinding force of plastic film, composite materials, adhesives, adhesive tapes, self-adhesive, medical patches, protective films, release papers, backplane materials, rubber, paper fibers and other products, The combustion and thermal conditions in the system are obviously different from the traditional combustion process (the air is at room temperature or below 600 ℃, and the oxygen content is not less than 21%). This technology will bring revolutionary development to the energy conversion technology based on combustion all over the world

the first exchange of this technology with the rest of the world began at the high temperature air combustion technology (HTAC) technology seminar held at the China Science and Technology Hall in Beijing in October 1999. Soon, such as Beijing Shenwu, Beijing Beidao energy technology development company, Beijing Science and technology competition nengjie, Shandong Boda, etc. launched a series of regenerative heat recovery technologies for industrial production. As far as the blast furnace hot blast stove is concerned, the self preheating method of the hot blast stove and the additional heating and heat exchange system of the hot blast stove belong to the application of high temperature air combustion technology in the blast furnace hot blast stove

2 additional heating and heat exchange system - the metal heat exchanger method is well used.

the additional heating heat exchange system is used in the No. 5 BF (2220m3) in dilingen, Germany

in the additional heating and heat exchange system adopted by rolle No. 5 blast furnace, two metal heat exchangers and a combustion furnace are built. The circulating waste gas can preheat the combustion supporting air to 500 ℃ and the gas to 250 ℃, and the blast temperature can be increased to 1285 ℃ with a single blast furnace gas with low calorific value (3000kj/m3)

this metal heat exchanger method is a combination of thermal equipment, which has high flexibility and exists independently of the hot blast stove. It can flexibly adjust the air and gas according to the change of the blast furnace state ◆ the preheating temperature with the test function of two boxes and three boxes, so as to increase or reduce the hot blast temperature and reduce or increase the amount of preheated air and gas. The utility model patent "preheating device of hot blast stove with additional combustion furnace" (Patent No. zl.0) has been applied successively in the blast furnaces of Angang No. 11 blast furnace (2580m3), Han steel 1 #, 3 #, 6 #, Shanxi Linfen, Taiyuan Steel 3 #, 4 #, Shandong Zibo, Qinggang 3 #, 4 #, Linyi, Baosteel Meishan 2 # (1280m3), Liaoning Beitai and other factories. The thickness of the insulation layer previously implemented according to the 50% energy-saving standard in all regions should be increased by more than 30%, The effect is remarkable

3 the self preheating method of blast furnace hot blast stove is mature.

the self preheating process of blast furnace hot blast stove is the first in China. So far, no foreign related literature has been retrieved. This process was first adopted by Lu Luping in July 1966 at the No. 3 blast furnace (100m3) of Jinan Iron Works, Shandong Province, and obtained the national invention patent. It has been 40 years since its invention. Generally speaking, it can be divided into three stages: (1) invention and original innovation stage; (2) Theoretical exploration and improvement stage; (3) Process improvement, large blast furnace application stage. During this period, many ironmaking and thermal engineering technicians conducted a lot of research

Anshan Iron and Steel Group has successively applied this self preheating process technology of hot blast stove with independent intellectual property rights on three 2580m3 blast furnaces, No. 10 (1994), No. 7 (2002) and future new No. 4 (2006). With the development and application of this technology, the corresponding theoretical exploration has also made important progress. Through computer numerical simulation, the unique superiority of this technology and the rationality of refractories are verified

4 the development of auxiliary hot blast stove method is in the ascendant

two auxiliary small hot blast stoves are used to burn excess blast furnace gas, alternately preheat the combustion supporting air of the large hot blast stove, and supply it for combustion of the large hot blast stove after temperature regulation. Greatly improve the physical heat of combustion supporting air to achieve a high air temperature above 1200 ℃. This technology can save a lot of high calorific value gas, and make more use of blast furnace gas, with remarkable economic benefits. The auxiliary hot blast stove method is adopted in two new 3200m3 blast furnaces in Angang. Some blast furnaces in Germany and Japan have also used regenerative hot stoves to preheat combustion supporting air

these technologies have the following characteristics in theory:

(1) it breaks the traditional concept of low-temperature waste heat recovery and greatly improves the preheating temperature of combustion medium. Although a certain amount of energy and investment have been added to the system, the output is far greater than the input by comprehensively analyzing the relationship between total energy consumption and benefits

(2) based on the use of inferior fuel, low-value blast furnace gas is used to obtain high-value high-temperature heat after process conversion. It is a real "resource-saving" process technology to save expensive high calorific value gas to supply more urgently needed departments, achieve rational allocation of energy, and create greater economic and social benefits

(3) the physical heat brought in by the preheating of the combustion medium is more useful than the same amount of chemical heat. This is because the flue gas temperature decreases and the thermal efficiency improves after the combustion medium is preheated, or the heat taken away by the flue gas is the same as that without preheating, so the recovered heat is more valuable

the large-scale, diversified and efficient hot blast stove

1 the leapfrog development of top burning hot blast stove

in the past 10 years, the wide application of top burning hot blast stove in our country has advanced by leaps and bounds. On the one hand, on the basis of summarizing the past experience, we have independently developed a variety of structural forms and boldly applied them; On the other hand, the introduction of foreign advanced technology has achieved gratifying results. Top burning hot blast stove has many advantages and is recognized by people

in the early 1980s, the industrial application of four top burning hot blast stoves in the new 2# blast furnace (1327m3) of Shougang caused considerable vibration in China. Handan Iron and Steel Co., Ltd. and Shijiazhuang blast furnaces have more than a dozen top burning hot blast furnaces, and Hunan Lengshuijiang No. 3 blast furnace has a new top burning hot blast furnace. Some small factories also use top burning hot blast stoves. Later, the ball type hot blast stove promoted the top burning type by a big step. Some domestic steel mills recognized its potential and adopted it one after another and independently researched and developed it. At present, the ball hot blast stove has been successfully applied to 1327m3 blast furnace. Now, a variety of top burning hot blast stoves have been widely used in our country

1) kalukin top burning hot blast stove is developing rapidly. The hot blast stove with this structure has been built and used on 1386 ~ 3200m3 blast furnaces in metallurgical plants in Russia and Ukraine. Kalugin top burning hot blast stove in Russia has been rapidly applied in China. For example, Laiwu Iron and steel 750m3, 1880m3, Jinan Iron and steel 1750m3, Huaihua iron and steel 450m3, Qinggang 500m3, Qian'an Liancheng 480m3, Guofeng 1800m3, Shouqin 1160m3, 2200m3, Tiangang 3200m3, Xianggang 2200m3, Angang 2800m3, Tangshan Iron and steel 3200m3 and Chongqing Iron and steel blast furnace hot stoves all adopt this structure. Anshan Iron and steel 2580m3 and Shougang Caofeidian 5500m3 blast furnace hot blast stoves are proposed to adopt Russian kalukin top burning hot blast stoves

2) universal application of ball hot blast stove ball hot blast stove can also be classified as a kind of top burning hot blast stove. The ball hot blast stove has small volume, simple structure, and the material consumption is much less than that of internal combustion hot blast stove, thus greatly saving investment. It has been well used in many small and medium-sized blast furnaces, such as Xinfeng in Hebei, Liugang in Guangxi, Xingcheng in Jiangsu and Weiyuan in Sichuan. At present, the ball furnace has been successfully applied to 1327m3 blast furnace

3) the rise of other top burning hot air stoves in China, Wuhan Hongtu, Chengde Hongbo, MCC Quantai, Xinxing cast pipe, etc. have also developed swirl and swirl top burning hot air stoves with independent intellectual property rights, which have been well applied

2 application of high air temperature and long life hot blast stove

the hot blast stove of hoogoven integrates a number of scientific and technological research achievements. Since its inception in 1969, it has been popularized and applied in dozens of blast furnaces in more than a dozen countries. The hot blast stove has the advantages of reasonable structure, low investment, less land occupation, high thermal efficiency, high air temperature and long service life

domestic research and development began in the 1970s, which is called high-temperature transformation internal combustion type. Limited to the technical level and the cost of refractory materials at that time