Apparatus and method for producing direct reduction iron from biological straws

Abstract

The invention relates to an apparatus and a method for producing direct reduction iron from biological straws. The apparatus comprise a preheating carbonization furnace and a reducing furnace, the preheating carbonization furnace is directly connected with the reducing furnace through a material conveying tube, and the preheating carbonization furnace comprise a feeding hoist, a bunker, a materialopening seal, a material distribution umbrella bed, a preheating carbonization chamber, a high temperature smoke collecting chamber, a reduction volatile part collecting chamber, a heater and a hightemperature smoke distributer, the reducing furnace comprises a reducing chamber, a fire channel, a fire channel segmentation wall, a combustor, a smoke discharging opening, a heat insulation chamberand a cooling and material discharging machine. The method comprises the following steps: generating combustible biogas and high temperature charcoal in the preheating carbonization furnace by using biological straw blocks, preheating iron ores in the preheating carbonization furnace to improve the temperature of the ores, adding the heated iron ores into the reducing furnace, reducing the iron ores, directly adding the high temperature charcoal into the reducing furnace together with the high temperature iron ores, and performing direct reduction. The apparatus and the method have the advantages of environmentally-friendly utilization of the biological straws, shortening of the material heating time to make the temperature of the material rapidly reach a temperature suitable for a reduction reaction, and saving of energy consumption and electricity consumption.

Description

technical field [0001] The invention relates to the field of metallurgy and non-blast furnace ironmaking, in particular to a device and method for producing direct reduced iron by utilizing biological straw. Background technique [0002] At present, there are two known methods for producing direct reduced iron in non-blast furnace ironmaking: one is gas-based direct reduction, and the other is coal-based direct reduction; the gas-based direct reduction method uses natural gas to produce the reducing gas through catalytic cracking , due to the lack of natural gas in China and Africa and the high price of natural gas, the gas-based reduction method is restricted in China and other countries that lack natural gas. At present, the production of reducing gas from coke oven gas in China is still in the research and development stage and is immature; the coal-based direct reduction method Including: rotary kiln method, tunnel kiln method, rotary hearth furnace method. The rotary ki...

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Problems solved by technology

[0002] At present, there are two known methods for producing direct reduced iron in non-blast furnace ironmaking: one is gas-based direct reduction, and the other is coal-based direct reduction; the gas-based direct reduction method uses natural gas to produce the reducing gas through catalytic cracking , due to the lack of natural gas in China and Africa and the high price of natural gas, the gas-based reduction method is restricted in China and other countries that lack natural gas. At present, the production of reducing gas from coke oven gas in China is still in the research and development stage and is immature; the coal-based direct reduction method Including: rotary kiln method, tunnel kiln method, rotary hearth furnace method. The rotary kiln method has high investment, high energy consumption, high equipment maintenance cost, and high operating cost. The high-temperature waste gas at the kiln tail must be transferred to other conversion and utilization equipment. The tunnel kiln method Low efficiency and high energy consumption, one ton of reduced iron is about 1.2t of coal, because silicon carbide tanks are used, and the life of silicon carbide tanks is 60 times on average, so the operating cost is relatively high

The rotary hearth furnace method has high investment and low reduction rate, and the reduction rate of domestically produced rotary hearth furnaces is lower than 90%.

[0003] With the improvement of the national environment and the improvement of people's awareness of environmental protection, biological straw is no longer used for cooking, heating and burning in rural areas. In addition, a large number of fruit tree pruning and wood waste are present. These materials are everywhere in our country and cannot be obtained. Full utilization is one of the main pollution sources of the rural environment; there are no natural gas and coal resources in the world, but countries rich in biological straw resources and iron ore resources, such as many countries in Africa, due to lack of coal and natural gas, steel cannot develop

[0004] After searching, the published Chinese patent with the application number 201710146951.3 is named as a method for the co-production of biomass gasification and direct reduced iron and the additives used. In an externally heated high-temperature container, the iron ore powder is reduced by reacting with the iron ore powder after the carbonization of the biomass, but this method produces wood tar during the carbonization of the biomass, which makes the wood tar adhere to the iron powder , the package of wood tar hinders the reduction of iron concentrate powder and reduces the reduction rate; in this method, the heating process of the material is heated outside the container, and the temperature rise of the material depends on the conduction between the materials, and the conductivity of the biomass itself is low, so The reduction time is long, the difference between internal and external reduction rates is large, and the energy consumption is relatively high. This problem needs to be solved urgently

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