Steel scrap preheater and preheating method of electric-arc furnace step disturbance culvert

Abstract

The invention discloses a scrap preheater of an electric-arc furnace step disturbance culvert. The scrap preheater comprises a heat-exchanging culvert, the low side of the heat-exchanging culvert is connected with a furnace, the high side of the heat-exchanging culvert is respectively connected with a smoke-collecting and dust-removing pipe and a feed sealing device, the heat-exchanging culvert comprises a material- conveying groove and a smoke guide cover, the material-conveying groove is used for conveying steel scrap materials to the electric-arc furnace, the smoke guide cover is covered on the material- conveying groove and is used for guiding smoke, the heat-exchanging culvert is provided with at least one cross-section abrupt change structure in the height-extending direction, and the cross-section abrupt change structure is used for disturbing the steel scrap material flow state and the smoke flow state. The invention further discloses a preheating method of the electric-arc furnace step disturbance culvert, and the steel scrap materials can be added to the material-conveying groove by the feed sealing device; the steel scrap material flow state is disturbed under the combined action of the cross-section abrupt change structure on the heat-exchanging culvert and horizontal vibration, so that the steel scrap materials have air permeability in a certain area; and the smoke flow state can be disturbed in the smoke guide cover, so that the smoke and the steel scrap materials can be subjected to heat exchanging fully.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a stepped disturbance channel scrap steel preheating device and a preheating method for an electric arc furnace. Background technique [0002] In electric furnace steelmaking, energy saving, environmental protection and consumption reduction have always been one of the core technologies in the development of global electric furnace steelmaking technology. There have been multiple designs at home and abroad in the past twenty years, but because of its technical difficulty, only a small amount of technology has been put into practical use at present, and its typical representatives are as follows: the finger shaft furnace disclosed in the German patent application whose publication number is DE4025249A1; US Patent Application No. US2007 / 0013112A1 discloses side thrust shaft feeding technology and US Patent Publication No. US5400358 discloses a vibrating continuous fe...

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Problems solved by technology

[0003] Among them, the preheating of shaft feeding uses flue gas to penetrate the scrap steel layer. The preheating energy saving effect is good, and the energy saving effect of 60-100kw.h per ton of steel can be achieved. However, its equipment is easily damaged by scrap steel, and the large amount of maintenance affects production.

And CONSTEEL is a horizontal continuous feeding technology, which can realize stable arc smelting in electric furnaces, is environmentally friendly and reduces electrode consumption, and can greatly reduce the production process costs of electric furnaces. However, in this technology, only the upper layer of scrap steel is heated, so the scrap steel preheating effect Poor, according to domestic and foreign reports, its average energy-saving effect is only 25kw.h per ton of steel; in addition, due to the need to improve the heat exchange efficiency with raw materials (scrap steel), the scrap steel in the conveying trough is relatively thin on the conveyor belt, which is inevitable Increase the length of the preheating section, resulting in a total equipment length of 90-100m, which is very unfavorable to the layout of the workshop; moreover, there is a serious air leakage in the dynamic seal in this technology, which requires a large capacity of the fan, etc. Defects

[0004] In order to improve the heat exchange efficiency in the continuous conveying process, the Chinese patent No. ZL201010270535.2 proposed by the applicant discloses a short-process scrap steel preheating conveying device, and proposes the idea of ​​heat exchange conveying in stepped troughs , to increase the contact area between the flue gas and the material (scrap steel) by diffusing the flue gas through the gaps between the steps, and improve the utilization efficiency of the waste heat of the flue gas. This idea can obtain better heat transfer efficiency in theory, but in the actual design process It was found that this short-process scrap steel preheating conveying device has the defects of complex ladder structure, very large heat load intensity (both sides are in direct contact with flue gas), poor reliability of the ladder, short working life and poor maintainability, and it is difficult to Overcome, in addition, the airtight door of the hot zone is also a danger point, in the sense that the reliability of the equipment is vetoed

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