Self-generating gas circulation tail-gas-emission-free scrap steel smelting system and steelmaking method

Abstract

The invention discloses a self-generating gas circulation tail-gas-emission-free steel scrap smelting system and a steelmaking method, and belongs to the technical field of metallurgy. The system involves a feeding system, a shaft furnace, a dust remover, a variable-frequency induced draft fan, a gas holder, a chimney, a coal gasification furnace, a cyclone dust remover, a liftable heat preservation cover, a material bin, a fine adjustment tundish and a steel ladle. The system utilizes high-temperature flue gas of the shaft furnace to inject coal to generate gas, gas self-circulation all-ironand steel scrap smelting is realized, and zero emission of flue gas in a smelting link can be realized, so that the effect of reasonable cyclic utilization of energy flow is achieved; meanwhile, the energy flow is more reasonable, and the heat consumption in the gas generation process is reduced, so that waste water treatment equipment and cost in the gas generation process are avoided; the energy-saving and emission-reducing effects are remarkable, the energy consumption in the smelting link is only about 25% of that of a traditional electric arc furnace, and the whole manufacturing cost is reduced by 180-260 yuan per ton of steel compared with the electric arc furnace; and the all-steel-scrap smelting process is a green smelting process integrating energy conservation, low carbon, environmental protection and low cost.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a self-generated gas circulation system and a steelmaking method for smelting scrap steel without tail gas emission. Background technique [0002] At present, there are two mainstream methods of iron and steel smelting: one is a long process, including mining, mineral processing, sintering, blast furnace ironmaking, converter steelmaking, refining, continuous casting and other processes; the other is a short process, including electric arc furnace or intermediate frequency Furnace melting, refining, continuous casting and other processes. Affected by the factors of discharge pressure and increasing scrap resources, the short process is favored by the industry. [0003] my country's power structure is dominated by thermal power generation, thermal power generation is the process of converting thermal energy into electrical energy, the highest conversion rate of thi...

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Problems solved by technology

[0003] my country's power structure is dominated by thermal power generation, thermal power generation is the process of converting thermal energy into electrical energy, the highest conversion rate of this process is about 40%, it can be seen that about 60% of the energy is wasted in this conversion process, and at the same time The operation process of power generation will also generate considerable operating costs. There will also be electricity transmission costs and losses in the transmission of electricity to electricity customers. The production process is a high energy consumption and high pollution process

It can be seen that from the perspective of energy flow and energy utilization rate, the electric arc furnace smelting process has the problems of high energy consumption, high cost and low conversion rate.

[0004] At present, there are many problems in the gasifier. Due to its structure, the coal at the top of the gas generation process is gradually heated up, and the coal is low-temperature dry distillation, which produces a large amount of long-chain organic matter, benzene, naphthalene, and tar substances. The gas must be eluted with water. In addition to these substances and dust removal, a lot of waste water is produced, and the environment is seriously polluted. Therefore, the government imposes strict restrictions on this process, which restricts the development of many gas-using enterprises.

In addition, the heat loss of this process is large, the control is complicated, and the calorific value of the gas produced is low, which greatly reduces the advantages of using gas

[0005] In addition, the sintering process fuel of most iron and steel enterprises in my country is using anthracite. The roasting process of the sintering process is a gradual heating process. The volatile matter in the coal is evaporated and escaped by distillation before reaching the ignition point. It is a huge waste of value, and at the same time, it becomes VOC when it is discharged into the atmosphere, polluting the atmosphere, and is currently the largest source of industrial VOC emissions.

Residential scattered coal combustion stoves have a very small volume, and the process of adding coal causes the furnace temperature to drop rapidly. The newly added coal is dry-distilled at low temperature, and the volatiles from the dry distillation have escaped without being burned, which not only loses the calorific value, but also causes VOC. escape, which is the biggest pollution of loose coal combustion

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