TWI468547B - Automatic nitroden humidifier controlling system in furance area - Google Patents

Description

Furnace area nitrogen humidification automatic control system

The invention relates to a nitrogen humidification automatic control system, in particular to a nitrogen humidification system used in a hot dip galvanizing process.

The electrochemical properties of zinc have a sacrificial protective effect on steel. Hot dip galvanizing has the characteristics of low cost and good corrosion resistance. It is widely used in various industrial applications. The corrosion resistance of hot dip galvanized steel sheets is mainly Two major characteristics: the protective effect of the surface film and the anti-corrosion effect. The surface film of the hot dip galvanized steel sheet is dense zinc oxide and zinc hydroxide, which will protect the bottom steel material from rust and invade the steel; another characteristic is because zinc The oxidation potential is higher than that of iron, so it is easier to oxidize than iron. The zinc around the steel will protect the steel to inhibit corrosion of the steel.

Referring to Fig. 1, this is a schematic diagram of a conventional hot dip galvanizing process. The steel coil (102) fed from the feed storage tower (101) enters the cleaning zone (103), which can be used to deposit oil and carbide on the surface of the steel sheet. Cleaned with iron powder to enhance the plating of subsequent processes and avoid the entry of contaminants into the zinc bath, and then enter the continuous annealing zone (104). The temperature of the steel at this stage is increased to the recrystallization temperature of the steel for recrystallization. Process. The steel sheet passing through the continuous annealing zone (104) is immersed in the zinc tank (105) at an appropriate angle and speed. The high temperature on the surface of the steel sheet evaporates a part of the zinc liquid in the zinc furnace, and the zinc ash produced by the evaporated zinc liquid It will spread around, some of which will accumulate in the furnace nose (106), and some will fall on the steel plate. As a result, irregular fine slag will be formed. This zinc ash will affect the quality of the galvanized steel sheet. When the humidity rises, the dew point temperature will also increase. The increase of the dew point temperature will make the surface zinc liquid in the zinc tank not easily evaporate. The inner wall of the furnace nose (106) will not easily produce zinc ash accumulation, but the dew point temperature is too high. It will also increase the thickness of the zinc oxide film on the surface of the steel too thick. This excessively thick zinc oxide film will cause strip-shaped zinc slag and easily cause scratch defects. Finally, the steel plate passing through the zinc tank (105) enters the uniform temperature cooling zone. (107) Performing cooling cooling, and then passing through the adjustment leveling zone (108) and the coating zone (109) and entering the discharge storage tower (110). Controlling the thickness of the zinc oxide film on the surface of the steel sheet can make it have good process slidability. More importantly, the zinc oxide film which appropriately controls the thickness of the steel surface can also help the stamping formability of the subsequent steel stamping process, so how to control the furnace The dew point temperature in the nose is an important issue.

2 is a schematic view of a conventional nitrogen humidification system. A dry nitrogen gas (201) is fed from an inlet to a humidification water tank (202) to form a wet nitrogen gas. The humidification water tank (202) has a water supply supplement line (203a). And a water flow outflow line (203b), the wet nitrogen flows out of the humidification water tank (202), passes through a flow meter (204) and enters a flow control line (205), which is used by the flow control line (205) A shut-off valve (206) and a regulating valve (207) are used for flow control, and subsequent wet nitrogen gas can be introduced into the furnace nose. The disadvantage of this type of humidifier system is that it can only supply wet nitrogen and cannot provide dry nitrogen at the same time. Therefore, with the difference in size and thickness of the steel plate, the same dew point temperature will be in the furnace nose, and there is no control temperature in the humidifier. In order to change the humidity of the wet nitrogen gas, it is impossible to ascertain the relative humidity or dew point data contained in the humidified nitrogen gas, which cannot meet the actual demand, and the water amount in the humidification water tank (202) cannot be surely known. The humidification water tank (202) will leave scale or impurities due to evaporation of water, which is easily accumulated in the humidification water tank (202) and cannot be removed.

The conventional humidification system needs to manually monitor the dew point and adjust the flow rate of wet nitrogen, which cannot be automatically controlled, and cannot timely and quickly respond to the change and demand of the dew point in the furnace zone. Therefore, zinc slag may be generated when the dew point is too high, and the dew point is too low. When the zinc ash is produced, the quality is very high.

The object of the present invention is to provide a nitrogen humidification system capable of automatically controlling the nitrogen dew point in the furnace nose, comprising: a humidifier for increasing the humidity of the nitrogen; and a dry nitrogen bypass line having an inlet and a second outlet. Wherein the inlet is a dry nitrogen tube, one outlet is a dry nitrogen tube introduced into the humidifier, and the other outlet is a wet nitrogen tube combined with the humid nitrogen of the humidifier to be introduced into the furnace nose; a dew point a sensor disposed between the wet nitrogen line connected to the nose of the furnace to detect the dew point temperature in the furnace nose; a heater disposed in the humidifier for changing the temperature of the water in the humidifier a plurality of shut-off valves are provided in the pipeline of the nitrogen humidification automatic control system for shutting off the flow and flow; and a water supply device is connected to the humidifier for providing the humidifier supplement.

By the present invention, a zinc oxide film can be stably and surely formed on the surface of the hot-dip galvanized steel sheet without impairing the surface appearance, and the means for blowing wet nitrogen into the furnace nose can change the dew point temperature in the furnace nose, and determine the relative Humidity and dew point temperature.

3 is a schematic view of a nitrogen humidification system (300) according to the present invention, comprising: a dry and wet nitrogen shunt tube (301), a dew point sensor (302) installed at a wet nitrogen outlet, and a humidifier (303), a heater (304) installed in the humidifier (303), a plurality of control valves (305a, 305b, 305c, 305d) and a water supply passage (306) connected to the humidifier, wherein The dew point sensor (302) is arranged between the wet nitrogen line connected to the nose to detect the dew point temperature in the furnace nose. The water supply channel (306) is used to provide the water quantity supplement of the humidifier (303).

The dry and wet nitrogen shunt tube (301) has an inlet and a second outlet, the inlet of which is a dry nitrogen line, one of which is introduced into the humidifier, and the other outlet is combined with the wet nitrogen of the humidifier (303). Introduced into the wet nitrogen tube in the above furnace nose. Another heating and cooling unit (307) is connected to the humidifier (303) for heating or cooling the water temperature in the humidifier (303) when the water temperature in the humidifier is too high or too low. It can be used for cooling or heating to improve the performance of the humidifier, which can be used as a backup heating and cooling unit for the above heater.

The humidifier (303) further has a filtered water circulation system (308) having a filter (308a), a circulation pump (308b) and a circulation line (308c), wherein one end of the circulation line Connected to the bottom of the humidifier (303), the other end introduces the filtered water into the humidifier (303) through the pipeline at the wet nitrogen outlet of the humidifier (303), and the water filtration circulation system (308) It can be used as a scale to remove scale in the humidifier to avoid scale accumulation in the humidifier (303). The humidification system (300) further has a liquid level sensor (309a) and a liquid level display (309b) for sensing the liquid level in the humidifier (303) and providing a signal to the water supply. The device supplements and maintains the amount of water in the humidifier.

A pressure reducing valve (313), a shut-off valve (305d) and a pressure gauge (312a) are additionally installed in front of the dry and wet nitrogen shunt pipe (301) for monitoring and controlling the flow into the dry and wet nitrogen shunt pipe (301). Nitrogen pressure, and two nitrogen flow controllers (310a, 310b) at the two outlets of the wet nitrogen shunt tube (301), respectively, can control the flow of nitrogen into the dry nitrogen line and the wet nitrogen line, respectively. The wet nitrogen outlet of the humidifier and the dry nitrogen line also have a total nitrogen flow control valve (310c) to control the flow of nitrogen into the furnace nose, and a shut-off valve (305b, 305c) is provided to control before entering the furnace nose. Whether the dew point detector (302) is turned on or off, the shut-off valve is used for shutdown and circulation.

An electromagnetic control valve (311) is provided at the water supply device (306) to control the flow of incoming water. In addition, the front end of the dry and wet nitrogen shunt tube (301) is further provided with a pressure reducing valve (313), a pressure gauge (312a) and a shut-off valve (305). The humidifier device has a pressure gauge (312b) for monitoring the pressure of the gas in the humidifier. The heater device has a water temperature gauge (312c) for monitoring the temperature of the water in the humidifier.

While the present invention has been described in its preferred embodiments, it is not intended to limit the scope of the invention, and various modifications and changes can be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

101. . . Feed storage tower

102. . . Steel coil

103. . . Cleaning area

104. . . Continuous annealing zone

105. . . Zinc tank

106. . . Furnace

107. . . Average temperature cooling zone

108. . . Adjusted leveling area

109. . . Coating area

110. . . Discharge storage tower

201. . . Dry nitrogen

202. . . Humidifying sink

203a. . . Water supply line

203b. . . Water flow outflow line

204. . . Flow meter

205. . . Flow control line

206. . . Shut off valve

207. . . Adjustment valve

300. . . Nitrogen humidification system

301. . . Dry and wet nitrogen shunt

302. . . Dew point detector

303. . . humidifier

304. . . Heater

305a. . . Shut off valve

305b. . . Shut off valve

305c. . . Shut off valve

305d. . . Shut off valve

306. . . Water supply unit

307. . . Heating and cooling unit

308. . . Filter water circulation system

308a. . . filter

308b. . . Cyclic pump

309a. . . Liquid level sensor

309b. . . Liquid level display

310a. . . Nitrogen flow controller

310b. . . Nitrogen flow controller

310c. . . Total nitrogen flow control valve

311. . . Electromagnetic control valve

312a. . . pressure gauge

312b. . . pressure gauge

312c. . . Water temperature meter

313. . . Pressure reducing valve

FIG. 1 is a schematic view of a conventional hot dip galvanizing process.

2 is a schematic view of a conventional nitrogen humidification system.

Figure 3 is a schematic view of a nitrogen humidification system of the present invention.

301. . . Dry and wet nitrogen shunt

302. . . Dew point detector

303. . . humidifier

304. . . Heater

305a. . . Shut off valve

305b. . . Shut off valve

305c. . . Shut off valve

305d. . . Shut off valve

306. . . Water supply device

307. . . Heating and cooling unit

308. . . Filter water circulation system

308a. . . filter

308b. . . Cyclic pump

309a. . . Liquid level sensor

309b. . . Liquid level display

310a. . . Nitrogen flow controller

310b. . . Nitrogen flow controller

310c. . . Total nitrogen flow control valve

311. . . Electromagnetic control valve

312a. . . pressure gauge

312b. . . pressure gauge

312c. . . Water temperature meter

313. . . Pressure reducing valve

Claims (7)

A nitrogen humidification automatic control system for use in a hot dip galvanizing furnace zone, comprising: a humidifier; a dry nitrogen splitting pipe having an inlet and a second outlet, wherein the inlet is a dry nitrogen pipe, one of which The outlet is a dry nitrogen tube introduced into the humidifier, and the other outlet is a wet nitrogen tube which is combined with the humid nitrogen of the humidifier to be introduced into the furnace nose of the hot dip galvanizing furnace; a dew point sensor is provided Between the wet nitrogen line connected to the furnace bottom of the hot dip galvanizing furnace to detect the dew point temperature in the furnace nose of the hot dip galvanizing furnace; a heater disposed in the humidifier for making The temperature of the water in the humidifier is changed; a plurality of shut-off valves are provided in the pipeline of the nitrogen humidification automatic control system as a cut-off and flow-off; and a water supply device is connected to the humidifier, which is used Provide a water replenishment for this humidifier. The nitrogen humidification automatic control system of claim 1 of the patent scope further includes a heating and cooling unit and is connected to the humidifier Inside, it is used to heat and cool the water temperature in the humidifier, and can be used as a backup heating and cooling unit of the above heater. The nitrogen humidification automatic control system of claim 1, wherein the humidifier has a filtered water circulation system having a filter, a circulation pump and a circulation line, wherein one of the circulation lines is terminated to At the bottom of the humidifier, take out the water to be filtered from the bottom of the humidifier, and at the other end, the filtered water is guided into the humidifier from the pipeline at the wet nitrogen outlet of the humidifier, thus providing a filter. water circulatory system. The nitrogen humidification automatic control system of claim 1 further includes a humidifier liquid level sensor and a display for sensing the liquid level of the humidifier and providing a signal to the water supply device. To replenish the amount of water to maintain the amount of water in the humidifier. For example, the nitrogen humidification automatic control system of claim 1 is characterized in that the front end of the dry and wet nitrogen partial flow line is further provided with a pressure reducing valve, a pressure gauge and a shut-off valve. For example, the nitrogen humidification automatic control system of claim 1 is characterized in that the dry and wet nitrogen flow dividing line is further provided with a dry nitrogen flow controller, a wet nitrogen flow controller and a total nitrogen flow controller for monitoring the pipeline. Nitrogen flow. The nitrogen humidification automatic control system of claim 1, wherein the heater device has a water temperature gauge for monitoring the water temperature in the humidifier.