SU1288478A1 - Recirculation continuous furnace - Google Patents

Abstract

The invention relates to metallurgical heat engineering and can be used in recirculation furnaces for heating ingots of non-ferrous metals before rolling and pressing at metallurgy and mechanical engineering plants. The purpose of the invention is to reduce energy consumption for the heating process. The furnace contains high-speed burners 1, a curved roof 2, walls 3, recirculation channels in the hearth 4 and in the side wall 5 connected to each other and to the mixers of injection devices 6, additional horizontal channels 7 made in the wall at the hearth level. The vault 2 has a slope in the direction opposite to the side wall 5 with burners. The recirculation channels of the furnace, connected to the orifice of the burners, ensure the multi-circuit circulation of flue gases in the working chamber of the furnace, intensify the heat exchange and reduce the energy costs of the process. 1 3.p. f-ly, 2 ill. i SL U2.1 / / Is9 00 00 th | 00

Description

The invention relates to metallurgical heat engineering and can be used in recirculation furnaces for heating ingots of non-ferrous metals before rolling and pressing at metallurgy and mechanical engineering plants.

The purpose of the invention is to reduce energy consumption for maintaining the heating process due to more intensive circulation of flue gases in the working space in the direction of the furnace axis from one circulation loop to another.

FIG. 1 shows the furnace, a cut hepe4Hbrii; in fig. 2 shows section A-A in FIG. 1, indicating the direction of movement of the circulating gases.

The furnace contains high-speed burners 1, a curved roof 2, walls 3, recirculation channels in the hearth 4 and in the side wall 5, interconnected with each other and with mixers of injection devices 6, additional horizontal channels 7 made in the walls at the hearth level.

The stove works as follows.

Due to the high speed of the expiration of the fuel combustion products, a vacuum zone is formed at the outlet of the high-speed burner, where moderately cooled exhaust gases are sucked through the recirculation channel. The gas mixture from the injection device is fed only under the roof. The curvilinear shape of the roof provides a three-circuit recirculation scheme for smoke glands. The lower recirculation contour is provided with a channel in the side wall of the furnace and a subfloor channel, the upper contour is provided with an additional channel and a vertical recirculation channel, the third contour due to local recirculation in the working volume of the furnace. It is characteristic of this furnace design and is formed in the longitudinal direction of the furnace axis between each pair of burners.

When the furnace is operating in the continuous metal heating mode, the movement of the charge and heating gases is countercurrent. With pas number arrangement of burners along the length of the furnace, the volume of gases from the metal unloading zone to the loading zone increases. In order to maintain the required heat load and heat flow fluxes in each section of the furnace, the fuel consumption on the burners is distributed taking into account its reduction towards the discharge of the metal, where

metal temperature is high and close to the final heating temperature. The fuel consumption and, therefore, the injection capacity of each burner is different, which determines the formation of an internal additional gas recirculation circuit in the furnace volume (the location of the return flow of gases in the direction of the longitudinal axis of the furnace) between each pair of burners.

The three-circuit gas recirculation scheme intensifies convective heat transfer and helps to level the floor of temperatures in the furnace working chamber. Increasing the share of convective heat transfer is especially important when heating ingots of non-ferrous metals, integral: the blackness of the surface of which is small and at temperatures of heating to ZOO-ZZO C is 0.13-0.2 for brass and 0.4-0.43 for copper . It should also be noted that the process of heating non-ferrous metals proceeds at relatively low temperature levels of the working medium, equal to 730-1000 s. In such furnaces, the convective proportion of total heat transfer dominates over radiant heat transfer.

Conducting heat treatment of non-ferrous metal ingots in the furnaces of the proposed design will allow for greater intensification of heat exchange and improvement of product quality.

Claims (1)

1. A recirculating through-furnace, containing a working chamber bounded by the vault, hearth, side and end walls, with recirculation channels in the hearth and side walls located in the same vertical plane and interconnected, gas burner devices located under the vault on one of the side walls, and a smoke duct, made at the furnace end, characterized in that, in order to reduce energy costs, additional horizontal channels are made in the wall with gas burner devices e hearth and connecting the working chamber to the recirculation channels in the wall and the WPR with gas burner devices. 31288478 2, the Furnace according to claim 1, about tl n h and th side, protomobilitno laterally gas wall with gas eagle devices. with the fact that the arch is made of curvilinear shape with an inclination in side flat side A wall with gas-powered devices. Heating eatable metal / Cumin gases - .2