Forging heating furnace capable of recycling waste heat step by step

Abstract

Flue gas in a flue gas channel is divided into a high-temperature area, a medium-temperature area and a low-temperature area, so that combustion-supporting air firstly absorbs heat in the low-temperature area and fully absorbs waste heat in the low-temperature flue gas, and then enters the high-temperature area to further absorb heat and fully absorb the waste heat in the flue gas after being heated; the temperature of combustion-supporting air is increased to the maximum extent; the steel billet in the steel billet preheating chamber and the flue gas perform reverse convection motion, the steel billet preheating chamber is long and large in space, the steel billet absorbs waste heat in the flue gas from a low-temperature area to a medium-temperature area in sequence, the temperature of the steel billet is continuously increased, and the heated steel billet enters a high-temperature area through a flue gas gate to continuously absorb heat and increase the temperature, so that the temperature of the steel billet is increased to the maximum extent; and waste heat cascade recovery and full utilization are realized. The device has the advantages of scientific and reasonable design, good combustion-supporting air and billet preheating effect, high flue gas heat energy recovery rate and the like.

Description

Technical Field

[0001] The invention relates to a forging furnace for recycling waste heat, in particular to a combined vehicle bottom type forging heating furnace for recycling waste heat in stages, belonging to the technical field of heat exchange. Background Art

[0002] Forging furnaces are commonly used heating equipment in the forging industry. The blanks are heated to the forging temperature in the forging furnace before forging. The temperature in the furnace often reaches over 1200°C. During the heating process, the high-temperature flue gas in the furnace must be continuously discharged out of the furnace, and a large amount of heat is lost in the flue gas, resulting in a huge waste of energy. For this reason, people have designed various flue gas heat recovery and reuse devices to recover the heat energy in the flue gas. However, in actual production practice, due to insufficient heat exchange in the recovery device, the temperature of the emitted flue gas is still high, and a large amount of heat energy is still discharged into the atmosphere, and the recovery rate is low. In summary, it is necessary to carry out multi-stage composite recovery and utilization of the high-temperature flue gas emitted by the forging furnace to improve the recovery rate of heat energy in the high-temperature flue gas. Summary of the invention

[0003] In response to the problems raised in the background technology, the present invention proposes a forging heating furnace with cascade recovery of waste heat, which divides the flowing flue gas into a high-temperature zone, a medium-temperature zone and a low-temperature zone, performs heat exchange in different zones, and realizes efficient utilization of cascade recovery of waste heat.

[0004] In order to achieve the above-mentioned object, the present invention proposes a forging heating furnace with stepwise recovery of waste heat, which comprises: a heating furnace, a blank and a heat exchange device, wherein the fuel gas and the combustion-supporting air are burned in the heating furnace to heat the blank and generate flowing smoke, and the smoke is discharged through a smoke exhaust channel, and is characterized in that:

[0005] The smoke exhaust channel is divided into a high temperature zone, a medium temperature zone and a low temperature zone;

[0006] The temperature of the high temperature zone is 650-500°C, the temperature of the medium temperature zone is 500-350°C, and the temperature of the low temperature zone is 300-150°C;

[0007] The heat exchange device comprises: a primary combustion air preheater, a steel billet preheating chamber and a secondary combustion air preheater;

[0008] The secondary combustion air preheater is arranged in the high temperature zone, the steel preheating chamber is arranged in the medium temperature zone and the low temperature zone, and the primary combustion air preheater is arranged in the low temperature zone;

[0009] The primary combustion air preheater is connected to the secondary combustion air preheater, and the normal temperature air enters the primary combustion air preheater to exchange heat with the flue gas in the low temperature zone, and the air absorbs heat and heats up before entering the secondary combustion air preheater to exchange heat with the flue gas in the high temperature zone, and the air absorbs heat and heats up again;

[0010] A smoke gate is provided between the high temperature zone and the medium temperature zone;

[0011] The smoke gate is closed, the smoke is divided into a high temperature zone and a medium temperature zone, the steel billets in the steel billet preheating chamber absorb heat and heat up in the low temperature zone and the medium temperature zone in turn, and the steel billets in the high temperature zone absorb heat and heat up in the high temperature zone;

[0012] The smoke gate is opened, the smoke in the high temperature zone is connected with the smoke in the medium temperature zone, and the billets in the billet preheating chamber enter the high temperature zone through the smoke gate.

[0013] Preferably, the secondary combustion air preheater is arranged outside the furnace cavity, and the flue gas enters the secondary combustion air preheater from the high temperature zone, and enters the medium temperature zone after heat exchange with the secondary combustion air preheater.

[0014] Preferably, the primary combustion air preheater is arranged outside the furnace cavity, and the flue gas enters the primary combustion air preheater from the low temperature zone and is discharged after heat exchange with the primary combustion air preheater.

[0015] Furthermore, the secondary combustion air preheater and the primary combustion air preheater are both arranged outside the furnace cavity, the flue gas enters the secondary combustion air preheater from the high temperature zone, and after heat exchange with the secondary combustion air preheater, enters the medium temperature zone; the flue gas enters the primary combustion air preheater from the low temperature zone, and after heat exchange with the primary combustion air preheater, is discharged.

[0016] The present invention is particularly suitable for a combined car bottom heating furnace, and the flue gas in the flue gas channel is arranged to be divided into three areas of high, medium and low temperatures, so that the combustion air first absorbs heat in the low temperature area and fully absorbs the waste heat in the low temperature flue gas, and then enters the high temperature area to further absorb heat after being heated, fully absorbs the waste heat in the flue gas, and maximizes the temperature of the combustion air; the billet in the billet preheating chamber moves in countercurrent with the flue gas, and because the billet preheating chamber is long and has a large space, the billet absorbs waste heat from the flue gas in the low temperature area → the medium temperature area in turn, so that the temperature of the billet is continuously increased, and the heated billet enters the high temperature area through the flue gas gate to continue absorbing heat and heating, thereby maximizing the temperature of the billet and realizing step-by-step recovery and full utilization of waste heat.

[0017] The invention has the advantages of scientific and reasonable design, good preheating effect of combustion-supporting air and steel billet, high flue gas heat energy recovery rate and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attached Figure 1 It is a schematic diagram of the main cross-sectional structure of the present invention.

[0019] In the attached drawings, 1 is a heating chamber, 2 is a burner, 3 is an air duct, 4 is a secondary air preheater, 5 is a flue gas connecting duct, 6 is a flue gas gate, 7 is a primary air preheater, 8 is an air inlet fan, 9 is an exhaust fan, 10 is a guide rail, 11 is a blank, 12 is a material car, 101 is a furnace top, 102 is a feed door, and 103 is a discharge door. a is a high temperature zone flue gas outlet, b is a flue gas outlet, A is a high temperature flue gas zone, B is a medium temperature flue gas zone, and C is a low temperature flue gas zone. DETAILED DESCRIPTION

[0020] As attached Figure 1 As shown, the material cart 12 carrying the blank 11 moves on the track 10 and enters the low-temperature flue zone C through the feed gate 102. When the blank 11 on the leftmost material cart 12 of the heating chamber 1 reaches the forging temperature, the flue gas gate 6 and the discharge gate 103 are opened, the feed gate 102 pushes the material cart 12, and the adjacent material carts 12 are pushed forward in sequence. The material cart 12 adjacent to the discharge gate 103 is pushed into the transfer vehicle from the discharge gate 103, and the material carts 12 in the high-temperature flue gas zone A, the medium-temperature flue gas zone B, and the low-temperature flue gas zone C respectively move forward by the position of one material cart 12. The flue gas gate 6 and the discharge gate 103 are closed, and the high-temperature flue gas enters the secondary air preheater 4 from the high-temperature zone flue gas outlet a, and then enters the medium-temperature flue gas zone B from the secondary air preheater 4 through the flue gas connecting pipe 5. The material carts 12 located in the low-temperature flue gas zone C→the medium-temperature flue gas zone B→the high-temperature flue gas zone A absorb heat and heat up in their respective areas. The air inlet fan 8 presses the air into the primary air preheater 7. After the primary air preheater 7 absorbs heat in the low-temperature flue gas zone C, it enters the secondary air preheater 4. After absorbing heat and rising in temperature, it enters the burner 2 from the air duct 3 to assist combustion.

[0021] In this embodiment, the secondary air preheater 4 is arranged externally on the upper part of the furnace top 101 .

[0022] The flue gas in the low-temperature flue gas zone C is discharged from the flue gas outlet b by the exhaust fan 9.

Claims

1. A forging heating furnace with step-by-step waste heat recovery, comprising: A heating furnace, a blank and a heat exchange device, wherein the fuel gas and the combustion-supporting air are burned in the heating furnace to heat the blank and generate flowing smoke, and the smoke is discharged through a smoke exhaust channel, characterized in that: The smoke exhaust channel is divided into a high temperature zone, a medium temperature zone and a low temperature zone; The temperature of the high temperature zone is 650-500°C, the temperature of the medium temperature zone is 500-350°C, and the temperature of the low temperature zone is 300-150°C; The heat exchange device comprises: a primary combustion air preheater, a steel billet preheating chamber and a secondary combustion air preheater; The secondary combustion air preheater is arranged in the high temperature zone, the steel preheating chamber is arranged in the medium temperature zone and the low temperature zone, and the primary combustion air preheater is arranged in the low temperature zone; The primary combustion air preheater is connected to the secondary combustion air preheater, and the normal temperature air enters the primary combustion air preheater to exchange heat with the flue gas in the low temperature zone, and the air absorbs heat and heats up before entering the secondary combustion air preheater to exchange heat with the flue gas in the high temperature zone, and the air absorbs heat and heats up again; A smoke gate is provided between the high temperature zone and the medium temperature zone; The smoke gate is closed, the smoke is divided into a high temperature zone and a medium temperature zone, the steel billets in the steel billet preheating chamber absorb heat and heat up in the low temperature zone and the medium temperature zone in turn, and the steel billets in the high temperature zone absorb heat and heat up in the high temperature zone; The smoke gate is opened, the smoke in the high temperature zone is connected with the smoke in the medium temperature zone, and the billets in the billet preheating chamber enter the high temperature zone through the smoke gate.

2. The forging heating furnace with stepwise waste heat recovery according to claim 1 is characterized in that: The secondary combustion air preheater is arranged outside the furnace cavity, and the flue gas enters the secondary combustion air preheater from the high temperature zone, and enters the medium temperature zone after heat exchange with the secondary combustion air preheater.

3. The forging heating furnace with stepwise waste heat recovery according to claim 1 is characterized in that: The primary combustion air preheater is arranged outside the furnace cavity, and the flue gas enters the primary combustion air preheater from the low temperature zone and is discharged after heat exchange with the primary combustion air preheater.

4. The forging heating furnace with stepwise waste heat recovery according to claim 1 is characterized in that: The secondary combustion air preheater and the primary combustion air preheater are both arranged outside the furnace cavity. The flue gas enters the secondary combustion air preheater from the high temperature zone, and enters the medium temperature zone after heat exchange with the secondary combustion air preheater; the flue gas enters the primary combustion air preheater from the low temperature zone, and is discharged after heat exchange with the primary combustion air preheater.

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