Firing an open-hearth furnace with natural gas

Autor: E. I. Bembinek, V. M. Smirnov, G. P. Gozhii, P. I. Tarim, V. D. Zelenskii, G. P. Pukhnarevich, I. I. Kobeza
Rok vydání: 1959
Předmět:
Zdroj: Metallurgist. 3:426-428
ISSN: 1573-8892
0026-0894
Popis: Natural gas is a valuable fuel for open-hearth furnaces since it has a high calorific value and does not contain harmful impurities. As part of the development of the national economy of the USSR from 1959 to 1965, the 21st Conference of the Communist Party has decided to increase the extraction and production of gas to 150 billion mS by the end of the seven years, thus providing the essential conditions for the extensive use of high calorie fuel for firing openhearth furnaces. The main difficulties arising when firing open-hearth furnaces with natural gas are due to the insufficient i l lumination of the flame when burning cold gas emerging at high speeds. To increase the illumination at the K. Libknekht and the Tagan Rog Steel Plants, fuel oil was added to the natural gas, the consumption of which is usually 30-40% based on the heat. The use of fuel oil for carburation of the flame requires the organization at the plant of a huge fuel oil system, which makes the construction of new shops more expensive and prevents openhearth furnaces operating on mixed gas from being converted to natural gas. There is also a method for increasing the illumination of the natural gas f lame by its self-carburation, i.e., decomposition of the methane with the formation of carbon black. When methane is heated in the absence of oxygen, i.e., thermal decomposition, hydrogen and carbon black are formed with a high degree of dispersion, being evenly distributed in the gas. As well as the carbon black there is a certain amount of tar and light oil, which also increases the illumination of the flame. When methane is heated in the presence of oxygen the products of the decomposition also contain carbon black and a certain amount of the heavy hydrocarbons. Consequently, by burning methane in the checkerworks with a coefficient of air excess less than unity, due to the thermal and oxidizing decomposition,decomposition products can be obtained which contain carbon black and the higher hydrocarbons which provide the necessary illumination of the flame. Under the direction of Academician N. N. Dobrokhotov, a method has been developed for firing open-hearth furnaces with cold natural gas with selfcarburation. In this method the natural gas before combustion in the working space of the furnace is preliminarily heated by the heat given out when a part of the gas burns in the head and also by the heat accumulated by the lining of the head. In the iron and steel casting shop of the K.Libknekht Plant, using the Ukrgipromez design, one of the openhearth furnaces was converted during the cold maintenance to firing with cold natural gas with self-carburation. Gas from the Shebelinskii deposit at a pressure of 2.5-3.0 arm was fed to the furnace along a gas pipe (Fig. 1) of diameter 4 in. in which there was a measuring diaphragm (to determine the total amount of gas supplied to the furnace) and a control valve. After the control valve the gas is fed to the heads of the furnace; in the gas pipes leading to the heads there are stop taps. Before changing over to natural gas, the open-hearth furnace operated with fuel oil and had one pair of slag chambers and two vertical air ducts. When the furnace was changed over to natural gas, a third middle vertical duct was made in the head, connecting the slag chamber with a water-cooled caisson arranged along the longitudinal axis of the working space as in the case of furnaces with gas firing. The design covers various methods for introducing the natural gas into
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