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Section 29 Blast Furnace Technical Documents
The blast furnace is the most difficult part of the entire project. In order to build the blast furnace, a special team was set up to collect everything about the blast furnace structure. Technical information on materials and construction methods. A 125-cubic-meter blast furnace is more than ten meters tall and weighs several thousand tons. It is the largest industrial equipment the elders have ever come into contact with, and its difficulty exceeds all previous industrial construction projects.
Structurally speaking, the blast furnace must meet two prerequisites: the charge can drop evenly; the furnace gas can rise evenly at all heights.
The uppermost part of a modern blast furnace is the furnace throat, and the charge is loaded into the furnace by a special charging machine above. In order to protect the furnace throat from being damaged by the collision of the furnace materials, a layer of steel bricks should be inlaid on it. The charge is added to the furnace throat and is immediately preheated by the hot furnace gas rising from below. The furnace gas is discharged from here through the pipe on the top of the furnace - this part must be sealed very tightly to prevent the gas, which accounts for most of the furnace gas, from leaking or returning and poisoning workers.
Part of the discharged furnace gas will re-enter the blast furnace as fuel, and the other part will be transported to the hot blast furnace to heat the blast.
The furnace body is a cone with a small top and a large bottom. The volume of the charge expands due to heat after contact with the furnace gas. In order to adapt to this expansion and enable the furnace charge to drop smoothly, the furnace body gradually becomes larger from top to bottom. This design is used to prevent hanging materials. The most important thing to avoid in a blast furnace is the accumulation of materials during combustion. This not only wastes the furnace materials, but also requires a ceasefire and cleaning in serious cases. In principle, blast furnaces do not cease fire production. Once a fire ceases, it will take a long time to resume production.
The finer the smelted ore particles, the greater the gas flow at the edge, so that the blast furnace will not hang materials. The flow of edge gas flow is related to the angle of the furnace body. During the lowering process of the furnace charge, the heavier ore tends to fall vertically. When the furnace body angle is small, the ore will be far away from the furnace wall, and a large amount of coke will move toward the furnace wall. At this time, a loose annular belt is formed near the furnace wall, which promotes the passage of a large amount of gas to form a large gas flow. When the furnace body is too steep, the opposite situation will occur - material hanging will occur. Therefore, the angle of the furnace body angle is generally 86 degrees.
Under the furnace body is the furnace waist, which is a cylindrical part designed to eliminate the dead space created by the furnace body. Below the furnace waist is the furnace belly. Due to the combustion of coke, the charge is continuously melted and the volume of the charge is increased. So its shape is big at the top and small at the bottom. The furnace hearth angle is generally 7682 degrees. Adopting a larger angle can reduce the friction of the furnace wall. At the same time, as the angle increases, the diameter of the furnace hearth is expanded, and the coke is fully burned, which improves the production efficiency of the furnace.
The bottom is the furnace hearth, where the molten iron and slag are stored. The temperature in the hearth is so high that just using ordinary refractory materials is not enough. The temperature in the hearth is enough to melt the refractory bricks in the hearth. The general approach is to install a cast steel or cast iron shell on the outer layer of the furnace wall, and install a serpentine cooling water pipe in the shell to cool and protect the internal refractory bricks. Because steel is difficult to cast - it flows very poorly. After studying it many times, a group of people from the industrial port felt that they were not confident in making such a large steel casting. Finally decided to settle for a large cast iron cooling jacket. Just this casting took Xiao Bailang several months to make.
The air inlets are located at the upper end of the furnace hearth. There are 8 air inlets in total. The air nozzles should protrude into the furnace wall. Due to the need to withstand high temperatures, the furnace nozzle is made of bronze. There is a cooling water pipe inside the furnace nozzle, which also provides uninterrupted water supply for circulating cooling during operation. The taphole is located near the bottom of the furnace, and above the taphole is the slag tapout. Also made of bronze and cooled by circulating water.
The blast furnace not only has a large capacity but also produces continuously. The temperature of the furnace throat of a large blast furnace is extremely high. Manual feeding cannot be used, but mechanical automatic feeding is used. There are several ways to charge the blast furnace. After discussion, Jiang Ye and Ji Wusheng decided to use the charging barrel charging method, which is the simplest mechanical structure. The charging barrel is bell-shaped. The hopper is transported to the top of the furnace, and then the charging barrel is raised to the top of the furnace to block the top of the furnace. Then the charge leaks from the bottom of the openable barrel into the furnace throat. The hopper slides on the track through a crank linkage mechanism to drive the barrel. Although this system is not complex, it requires the industrial system to provide reliable equipment in terms of chains, mechanical transmissions and power machinery.
Jiang Ye said: "At the beginning, Zhan Wuya could not say that he only built converters for blast furnaces and imported pig iron from Guangdong to make steel. I also thought he was a bit of a right-leaning conservatism - now it seems that even if he wanted to build a blast furnace at that time, he might not be able to do it."
"At that time, you could only build a three- to five-meter-high earthen blast furnace. Two to three tons of pig iron could be produced in a day and night, and the top of the head was five tons. Most of the feeding was done by using a winch to winch up the furnace material, and then the workers shoveled it into the furnace throat. Riga - The workers were beaten to death. The feeding was slow and the blanking was uneven. The efficiency was as bad as that of today's small chemical plants." Ji Wusheng sympathized with the owners of the chemical system. According to the standards of the old time and space, the industrial scale of his family is not even comparable to the county-level chemical plants of the 1970s. Many products are still manufactured at the laboratory level. If it were not for the coal coking joint production plant transported by air from the old time, it would still be strong. The spectacular scene, the pitiful output of the 800-ton ammonia and electrolytic salt workshop alone made him roar at every Planning Institute meeting.
"Once our steel complex is put into production, we will probably use chemical equipment on a large scale. Your mechanical department will have a heavy burden."
"It doesn't matter." Jiang Ye didn't care. "Can you produce some special steel or special stainless steel? There are too many places to use it. There is also silicon steel, which is needed to make generators, motors and transformers. You don't I know that Chang Gong comes to our place every three days and complains that there is no use for him in power construction."
The power supply of Chuan Chuan Group is a fatal shortcoming. Whether it is power generation, power supply or power usage, it is probably the level of small counties in the late 1970s - or even worse - it is not possible to build a county-wide power grid. . The direct result of the lack of electricity is the proliferation of steam engine boilers everywhere.
"Your request is more difficult. We cannot get the non-ferrous metals needed for the former, and it is difficult to smelt the latter. However, manganese steel can be produced quickly - the iron ore in Tiandu itself contains high manganese, and the local There is a manganese mine that can be mined." Ji Wusheng said, "Besides, Chang Gong has not been planning the East Asia Power Grid's ultra-high voltage transmission and transformation system, Himalayan super power station, and Yangtze River cascade power station development plan in his notebook - he can work as an electrician while first Make a plan?"
"Although it is not as exciting as stainless steel and silicon steel, it is still good news." Jiang Ye said. Manganese steel has the characteristics of high strength and high wear resistance, and plays an important role in many large machinery. With manganese steel, the performance of current low-quality bearings, gears, structural parts, and connectors can be greatly improved. Manganese steel can also be used to manufacture knives for industrial use and provide high-quality weapon steel for the military industry.
Next to the blast furnace stands the completed large-scale hot blast furnace - the blast volume required by the 125 cubic meter blast furnace far exceeds that of several small converters and iron melting furnaces in the past. Bigger often means greater efficiency. The hot blast furnace has been built during the converter steelmaking workshop and has considerable experience in construction and use. This time there are enough refractory materials, not only the volume has become larger, but the internal structure has also been optimized. The new hot blast stove is a quite satisfactory Kaopa-type hot blast stove, which is 10 meters high. The hot blast furnace uses the high-temperature exhaust gas of the blast furnace to preheat the air entering the blast furnace from the blower. The design goal is that the air outlet temperature can reach 620C. At such a high temperature, the reducibility of iron ore will reach its highest level, and coke consumption can be reduced by one-fifth.
"Jiang Gong," a naturalized citizen intern hurried over, "The gas plant site just called and asked you to go take a look. There are some problems there."
"Okay, I'll be there right away." Jiang Ye and Ji Wusheng said hello and went down the hill. A farm vehicle had been prepared here.
The gas plant is an important project of the Ma Niao Consortium. The coal-coking combined chemical plant put into use in Bopu can also provide coal gas, but because it has chemical equipment for subsequent processing and refining of gas and tar produced during coking. Therefore, coal gas is generally consumed directly as a chemical raw material, and a small amount of the remaining gas is given to the Bopu Industrial Zone as fuel.
The gas plant does not use coking lignite specially transported from the Jiazi Coal Mine - the blast furnace coke is provided by the Bopu Coal and Coke Combined Plant - but uses a dedicated gas generator to retort various inferior coals. The purpose of its production is not to obtain coke. But gas.
After the gas workshop is completed, it will provide gas fuel for the entire plant, and its main purpose is to provide fuel for open-hearth steelmaking - the calorific value of the gas produced in blast furnace smelting is low and cannot be used as fuel for the open-hearth furnace.
Unlike specialized large coke ovens in coking plants, gas generators have a simple structure and are easy to operate. Moreover, the company also has a lot of experience in manufacturing and using gas generators. No difficulty in making and using.
After the coal is added to the generator furnace, it is ignited for carbonization and reacts with the air added from the bottom of the furnace to produce gas. However, the calorific value of gas at this time is low, and it is low as an open-hearth fuel. Therefore, while coking, the water vapor produced by the boiler evaporator is mixed with air in proportion and then blown into the generator furnace to produce half-water gas and half-water gas. The calorific value is much higher than that of air gas, so it can be used as a fuel for open-hearth furnaces.
The tar produced during carbonization is stored in a special tar tank and then transported to the Bopu Coal and Coke Combined Plant for further refining. Ji Tuisi plans to install a tar treatment plant in Ma Niao Gas Plant in the future to process coal tar on site to produce chemical products. ,.
