SU851047A1 - Method of heat neutralizing of cupola gases - Google Patents

Description

one

The invention relates to a foundry and can be used for dust cleaning and heat recovery of cupola waste gases. j

There is a known method of neutralization of cupola gases, based on the selection of idle galoshes from the oxygen ozone, i.e. from the lance area, where Q carbon monoxide does not have time to form in large quantities, and the temperature of the gases is maximum and is 1800-2000 ° C with subsequent removal to a separate heat exchanger.

However, this method does not eliminate CO emissions into the atmosphere during periods of the beginning of smelting, when the charge does not completely fill the cupola chamber, and its temperature is low during periods of fusion, when the height of the charge column and, accordingly, its hydraulic resistance decreases. At the same time, the heat recovery efficiency 25 is also sharply reduced. Since the bulk of the gases at the full charge charge is discharged from the mine of the cupola, the heating of the charge and the efficiency of the furnace drastically decrease. 30

The purpose of the invention is to increase the stability of the afterburning of the gases leaving the cupola.

This goal is achieved by taking gases from the reduction zone in the amount of 5–20% of the total volume of cupola gases with a temperature of 1100–1300 ° C and carbon monoxide concentration of 16–26%, and air in the amount of 20–30% is introduced into the stream of selected gases. from stoichiometric and after mixing is fed into the mine above the charging port.

When selected high-temperature gases are introduced into the cupola tube or the combustion chamber, where the mixture of cupola gases with air is supplied, they ignite, reaching an average temperature of 1500-1800 C. This ensures stable ignition of the whole mass of the mixture of cupola gases with air, without the need for additional fuel. or combustion stabilizers. The gases are withdrawn from the eduction zone of the cupola chamber without flow boosters due to the overpressure in the cupola mine.

Claims (1)

When the level of the charge column of the cupola is lowered, the temperature of the main stream of exhaust gases increases and the amount of gases withdrawn from the reduction zone decreases, which maintains the same heat balance and stability of thermal neutralization (by reburning). The limits of the parameters for providing the thermal afterburning method are established, based on the fact that the minimum volume of gases taken from the reduction zone is set at 5%, since the heat content of the cupola, gases in this zone is 800-1000 kcal / m is the lower limit, which provides the temperature of 1,507-7,800c during self-ignition and thermal deactivation of the main flow of cupola gases in a pipe or a combustion chamber} a maximal volume of the selected gases of 20% ensures the set goal and does not disturb the course of the cupola melting: heating temperature ichts, furnace efficiency, productivity, etc:, the limits of the air supply to the gases selected from the reduction zone are set at 20-30% of the stoichiometric volume necessary for combustion, which ensures preliminary mixing and preparation of gases for self-ignition when they enter a space with a sufficient amount of oxygen (air) in the cupola tube or the combustion chamber and prevents them from igniting along the route before entering the chamber; 110 The minimal rate, the range of the gases being taken, is sufficient for their stable combustion and exceeding the self-ignition temperature: —the maximum for the gases being withdrawn, limiting the maximum concentrations of CO, with increasing temperature of the gases being withdrawn and, accordingly, lowering the level of withdrawal, the concentration of CO in gases decreases the concentration of carbon monoxide in the sampled gases for the purpose of using them as fuel is selected, based on practical data on the cessation of gases in the cupola mine in the zone above x temperature: the upper limit of the content of carbon monoxide in the cupola gases usually does not exceed 26%, the lower limit of 15% - the minimum concentration of carbon monoxide in ensuring stable combustion gases selected | the amount of gases selected depends on the ratio of the cross-sectional areas of the cupola mine and the gas pipeline and the pressure difference in the extraction zone and the cupola pipe: the temperature and concentration of carbon monoxide in the extraction gases depends on the level of their extraction from the cupola mine. These limits occur when gas is taken at a distance of 800–1,200 mm above the tuyere level. The proposed method does not require for its implementation automatic regulating, monitoring devices or safety automation, as well as the consumption of additional energy or fuel. To carry out the proposed method of thermal neutralization, a cupola tube or a combustion chamber of heat exchangers is used, i.e. No additional facilities or afterburners, as well as chimneys, smoke exhausters and gas shut-off equipment are required. The heat obtained can be used in heat exchangers, utilizers or directly for heat treatment. Claims The method of thermal neutralization of cupola gases, including partial selection of cupola gases from the hearth, followed by their return to the afterburning zone of the cupola mine, characterized in that, in order to increase the stability of afterburning, gases are taken from the reduction zone in an amount of 5-20% of the total cupola gases with a temperature of 1100-1300 s and a carbon monoxide concentration of 16-26%, air is introduced into the stream of selected gases, in an amount of 20-30% of stoichiometric gas and, after mixing, is fed into the mine above the charging port. Sources of information taken into account in the examination 1. A. Clausen. Climbing flames on the mountain than the blast. TsBTI MTSHM, M ,, 1958, S.2527.