Jet-type direct-fired preheating system

Patent metadata

Field	Value
Publication number	US-2026085374-A1
Application number	US-202319110174-A
Country	US
Kind code	A1
Filing date	Sep 15, 2023
Priority date	Sep 15, 2022
Publication date	Mar 26, 2026
Grant date	—

Abstract

A jet-type direct-fired preheating system, comprising a direct-fired furnace and a preheating furnace. The direct-fired furnace comprises a furnace casing, a direct-fired heating area being provided in the furnace casing. The preheating furnace comprises: a furnace body, wherein the upper portion of the furnace body is connected to the upper portion of the direct-fired furnace by means of a communicating pipe, the bottom of the furnace body is provided with a strip steel inlet, a sealing apparatus and a steering roller, an upper collection chamber of direct-fired waste gas and a secondary combustion chamber of direct-fired combustion waste gas are provided at the upper portion in the furnace body, and a lower collection chamber of the direct-fired waste gas is provided at the lower portion in the furnace body; and a plurality of heat exchange and jet bellows units, provided in the furnace body in the height direction of the furnace body, a threading channel being formed in the middle. Each heat exchange and jet bellows unit comprises: a bellows body, a heat exchange pipe being provided in the bellows body, and a nozzle being provided on the side surface opposite to the threading channel; a secondary waste gas mixing chamber provided between the bellows bodies; and a circulating fan, an inlet pipeline port being formed in the threading channel, and an outlet pipeline port being located in the bellows body. According to the present invention, strip steel can be quickly preheated to 350° or above and quickly heated to 750° or above; and waste heat of the waste gas is fully utilized, such that an over-thick oxide layer can be prevented from being generated on the surface of the strip steel.

First claim

1 . A preheating furnace, which comprises:
a furnace body, which is provided with at least two connecting holes on the upper side wall, symmetrically arranged on the left and right, wherein the connecting holes connect through holes of the upper part of the furnace shell of the direct fire furnace through a communicating pipe respectively; wherein the top of the furnace body is provided with a furnace throat corresponding to a furnace top roller chamber of a direct fire furnace for passing the strip steel; the bottom of the furnace body is provided with a strip steel inlet and a corresponding sealing device and a steering roller; the upper part of the furnace body is provided with an upper partition plate with a threading hole to form an upper gas collection chamber for direct fire exhaust gas; a secondary combustion chamber for direct fire combustion exhaust gas is provided below the upper gas collection chamber for direct fire exhaust gas, and at least one open flame burner is provided in the secondary combustion chamber for direct fire combustion exhaust gas; the lower part of the furnace body is provided with a lower partition plate with a threading hole to form a lower gas collection chamber for direct fire exhaust gas, which connects an exhaust gas fan through an exhaust gas discharge pipeline; a plurality of heat exchange and jet bellows units, which are arranged on two sides below the secondary combustion chamber for direct fire combustion exhaust gas in the furnace body along the height direction of the furnace body, wherein a threading channel for passing the strip steel is formed in the middle; wherein each heat exchanger and jet bellows unit comprises, a bellows body, which is vertically provided with a plurality of heat exchange pipes, wherein the bellows body is provided with a plurality of nozzles on the side opposite to the threading channel; wherein an exhaust gas secondary mixing chamber that is communicated with the heat exchange pipe is provided between the bellows bodies that are arranged up and down; a circulating fan, wherein an inlet pipeline port is arranged in the threading channel, and an outlet pipeline port is located in the bellows body; a plurality of sealing devices that can be passed through by the strip steel are respectively arranged at the upper and lower ports of the threading channel and the threading holes of the upper and lower partition plates.

2 . The preheating furnace according to claim 1 , wherein a combustion exhaust gas thermometer is further provided in the secondary combustion chamber for direct fire combustion exhaust gas.

3 . The preheating furnace according to claim 1 , wherein the sealing device is a nitrogen gas sealing structure, which adopts a nitrogen gas sealing chamber with a nitrogen gas injection pipeline arranged thereon.

4 . The preheating furnace according to claim 1 , wherein the exhaust gas discharge pipeline is connected to a waste heat boiler and a chimney.

5 . The preheating furnace according to claim wherein a control valve is arranged on the exhaust gas discharge pipeline.

6 . The preheating furnace according to claim 1 , wherein a shielding gas of nitrogen and hydrogen is introduced into the bellows body.

7 . A jet direct fire preheating system, which comprises: a direct fire furnace, a preheating furnace; wherein
the direct fire furnace comprises: a furnace shell, wherein a furnace top roller chamber and a furnace bottom roller chamber are respectively provided at the upper and lower ends; steering rollers are respectively arranged in the furnace top roller chamber and the furnace bottom roller chamber; a plurality of direct fire heating zones are arranged in the furnace shell along the height direction, and a plurality of direct fire burners are arranged in the direct-fire heating zone; at least two through-holes are provided on the upper side wall of the furnace shell, and are symmetrically arranged on the left and right; the preheating furnace comprises: a furnace body, which is provided with at least two connecting holes on the upper side wall, symmetrically arranged on the left and right, wherein the connecting holes connect through holes of the upper part of the furnace shell of the direct fire furnace through a communicating pipe respectively; wherein the top of the furnace body is provided with a furnace throat corresponding to the furnace top roller chamber of the direct fire furnace for passing the strip steel; the bottom of the furnace body is provided with a strip steel inlet and a corresponding sealing device and a steering roller; the upper part of the furnace body is provided with an upper partition plate with a threading hole to form an upper gas collection chamber for direct fire exhaust gas; a secondary combustion chamber for direct fire combustion exhaust gas is provided below the upper gas collection chamber for direct fire exhaust gas, and at least one open flame burner is provided in the secondary combustion chamber for direct fire combustion exhaust gas; the lower part of the furnace body is provided with a lower partition plate with a threading hole to form a lower gas collection chamber for direct fire exhaust gas, which connects an exhaust gas fan through an exhaust gas discharge pipeline; a plurality of heat exchange and jet bellows units, which are arranged on two sides below the secondary combustion chamber for direct fire combustion exhaust gas in the furnace body along the height direction of the furnace body, wherein a threading channel for passing the strip steel is formed in the middle; wherein each heat exchanger and jet bellows unit comprises, a bellows body, which is vertically provided with a plurality of heat exchange pipes, wherein the bellows body is provided with a plurality of nozzles on the side opposite to the threading channel; wherein an exhaust gas secondary mixing chamber that is communicated with the heat exchange pipe is provided between the bellows bodies that are arranged up and down; a circulating fan, wherein an inlet pipeline port is arranged in the threading channel, and an outlet pipeline port is located in the bellows body; a plurality of sealing devices that can be passed through by the strip steel are respectively arranged at the upper and lower ports of the threading channel and the threading holes of the upper and lower partition plates.

8 . The jet direct fire preheating system according to claim 7 , wherein a combustion exhaust gas thermometer is further provided in the secondary combustion chamber for direct fire combustion exhaust gas.

9 . The jet direct fire preheating system according to claim 7 , wherein the sealing device is a nitrogen gas sealing structure, which adopts a nitrogen gas sealing chamber with a nitrogen gas injection pipeline arranged thereon.

10 . The jet direct fire preheating system according to claim 7 , wherein the exhaust gas discharge pipeline is connected to a waste heat boiler and a chimney.

11 . The jet direct fire preheating system according to claim wherein a control valve is arranged on the exhaust gas discharge pipeline.

12 . The jet direct fire preheating system according to claim 7 , wherein a shielding gas of nitrogen and hydrogen is introduced into the bellows body.

13 . The preheating furnace according to claim 4 , wherein a control valve is arranged on the exhaust gas discharge pipeline.

14 . The jet direct fire preheating system according to claim 10 , wherein a control valve is arranged on the exhaust gas discharge pipeline.

Assignees

• Baoshan Iron & Steel

Inventors

• Zhang Liyang
• Li Jun
• Wang Junfei
• Wan Zhaotang
• Wang Yanhui

Classifications

• F27D2019/0021

  Monitoring the temperature of the exhaust gases · CPC title

• F27D2007/045

  Fans · CPC title

• F27D2003/0042

  comprising roller trains · CPC title

• F27D99/0075

  Gas curtain seals · CPC title

• F27D19/00

  Arrangements of controlling devices · CPC title