RU2145036C1 - System of recovery of high-temperature gas heat - Google Patents

Abstract

FIELD: recovery of heat of high-temperature gases after heat-treatment furnaces. SUBSTANCE: system includes furnace, flue, convective loop recuperator, and distributing and accumulating collectors in which moving partitions dividing recuperator into independent tubular elements are installed. It allows use of given system for heating of air intended for burning and for air heating in amount required for heating of department. In this case, heat exchange conditions are preserved for both air and products of burning. EFFECT: higher efficiency. 2 dwg

Description

 The invention relates to the field of use of secondary energy resources (VER) and can be used, for example, to recover heat from high-temperature gases after thermal furnaces.

 Known heat recovery systems for high-temperature gases, containing a furnace and convective heat exchanger [1].

 The closest in technical essence and quite effective is the heat recovery system of high-temperature gases [2]. This system is designed for the complex step-wise use of the heat of the exhaust gases of heating furnaces as part of individual heat exchangers for each furnace in combination with an air heater common to a group of furnaces. First of all, the heat used is taken away from the furnace with flue gases in a closed (recuperative) cycle by heating the combustion air in the recuperator. Further, in an open circuit, the heat of the exhaust gases is used to heat the air, but already for heating and ventilation purposes.

 A disadvantage of the known heat recovery system for high-temperature gases is that they have independent heat exchangers for heating the air only in the amount necessary for burning fuel in the furnace and heating the combustion air.

 The aim of the invention is to expand the scope of application of the heat recovery system of high-temperature gases by installing one recuperator both for heating the combustion air and for heating the air in an amount necessary for heating the workshop.

 The task is ensured by the fact that in the proposed heat recovery system of high-temperature gases, which contains a furnace and a convective loop heat exchanger integrated into the chimney, distributing and collecting air collectors, the heat exchanger is equipped with movable partitions that separate them into autonomous working collectors with independent and tubular elements.

 The technical result is achieved by the fact that for heating the air going to combustion, the movable partitions are lowered, while the number of tubular elements connected in parallel through the air is reduced. By reducing the cross section through the air, its speed remains within acceptable limits. To heat the air for heating, the movable partitions rise and all the tubular elements work in parallel through the air. In this case, the air flow can be increased several times, while its speed will remain within acceptable limits.

 As a result, in both cases, heat transfer conditions are retained both from the air side and from the side of combustion products. Thus, in the winter, the recuperator can heat a large amount of air necessary for heating, and in the summer, heat the combustion air.

 In the drawing (Fig. 1) is a schematic representation of the proposed heat recovery system for high-temperature gases. The system includes: a thermal furnace 1 with a chimney 2, in which a convective loop heat exchanger 3 is installed, consisting of tubular elements 4, distributing and collecting manifolds 5, 6, in which movable partitions 7 are installed, the distributing collector 5 of the recuperator 3 is connected to the supply duct 8, the collecting manifold 6 of the recuperator 3 by the exhaust duct 9 is connected to the burner 10, and the exhaust duct 11 is connected to the heating system of the workshop. Air ducts 9 and 11 have a gate 12 and 13.

 In the drawing (Fig. 2), a convective loop heat exchanger 3 is schematically shown, comprising: tubular elements 4, distributing and collecting collectors 5, 6, movable partitions 7.

 The heat recovery system of high-temperature gases works as follows. The combustion products generated during the combustion of fuel in the furnace 1, enter the chimney 2 and pass through a convective loop heat exchanger 3, cold air through the duct 8 is supplied to the distributing manifold 5, from where it enters the tubular elements 4, where it is heated and enters the collecting manifold 6 .

 When heating the air for heating partitions 7, installed in the distributing and collecting manifolds 5, 6, rise and all the tubular elements 4 of the convective loop heat exchanger 3 work in parallel through the air. The gate 12 is in the closed position, and the gate 13 is open. Heated air through the duct 11 is used for heating the workshop.

 When heating combustion air, the movable partitions 7 installed in the distributing and collecting manifolds 5, 6 are lowered and the convective loop heat exchanger 3 is lowered into independent tubular elements 4 connected in series through the air. The gate 12 is in the open position and the gate 13 is closed. Heated air through the duct 9 is supplied to the burner 10.

 This system of heat recovery of high-temperature gases can be used both for heating a small amount of air going to combustion, and for heating air in the amount necessary for heating the workshop. At the same time, in both cases the air speeds will be within acceptable limits, and the heat transfer conditions will remain the same. This provides additional reliability for the operation of the recuperator with variable parameters of the products of combustion and air when it is installed behind batch furnaces.

Sources of information
1. Lemlekh I.M., Gordin V.A. High-temperature air heating in the steel industry, pp. 199-200
2. Grigoriev V.N. Improving fuel efficiency in industrial furnaces. M.: Metallurgy, 1997, p. 221 - 222.

Claims (1)

 A heat recovery system for high-temperature gases, comprising a furnace, a chimney with a built-in convective loop heat exchanger, the distributing and collecting collectors of which are connected to the supply and exhaust ducts, characterized in that the distributing and collecting air collectors of the heat exchanger are equipped with movable partitions that separate them into autonomously working collectors with tubular elements.

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