JPS5946314B2 - Metal strip continuous annealing pickling equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in continuous annealing and pickling equipment for metal strip.

The continuous annealing and pickling equipment for metal strips, which is generally used in AP lines for metal strips such as steel and copper alloys, consists of an annealing furnace 1, a degreasing device 2 as equipment before and after the annealing furnace, and a drying device for drying after degreasing, as shown in Fig. 1. A drying device 3, a water cooling tank 4, a drying device 5 for drying after water cooling, a pickling device 6, a hot water washing device 7, a drying device 8 for drying after hot water washing, etc. are provided.

Conventionally, a boiler 9 is provided to supply hot air to the drying devices 3, 5, and 8, heat the pickling liquid in the pickling device 6, and supply hot water to the hot water washing device 7. The steam was passed through each heat exchanger 10, 11, 12, 13, and 14 to heat the air pickling liquid, water, and the like. Therefore, in this conventional apparatus, a boiler is required as a heating source for the equipment before and after the annealing furnace, and heat loss in the boiler and each heat exchanger is large, and the thermal efficiency for heating is also low. On the other hand, a water-cooled heat exchanger 15 is provided in each zone of the cooling zone 1a of the annealing furnace, and as shown in FIG. 2, the atmospheric gas cooled by the heat exchanger is circulated by a circulation fan 216 to the strip IT. The strip is sprayed to provide indirect cooling of the strip through convective heat transfer. The heat transferred from the strip IT to the cooling water of the heat exchanger 15 in this way (hereinafter referred to as cooling heat) amounts to a considerable amount of heat, but conventionally, this cooling heat is discarded without any use. was. This invention was made in view of the above points, and by using the cooling heat of the strip in the annealing furnace as a heating source for the front and rear devices of the annealing furnace, 3. Equipment costs and operating costs can be significantly reduced. It is an object of the present invention to provide a continuous annealing and pickling apparatus for metal strips.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4.

In the figure, parts such as the annealing furnace 1 denoted by the same reference numerals as in FIG. 1 indicate the same parts as in FIG. 1.

Reference numeral 21 denotes an air-cooled heat exchanger provided in the first zone of the cooling zone 1a of the annealing furnace, which is arranged in the same manner as the heat exchanger 15 in FIG.
7 is indirectly cooled.

22 is a cold air flow path connected to a cold air supply source such as a blower (not shown), 23 is a cold air flow rate control valve, and 24 is a hot air flow path after flowing through the heat exchanger, which is connected to the drying devices 3, 5, and 8. has been done.

25 is a hot air temperature detector, 26 is a temperature transmitter, and 27 is a temperature controller.

Further, 28 is a pressure transmitter that detects the pressure in the hot air flow path 24 and issues a pressure signal, 29 is a pressure regulator, and 30 is a hot air release valve. On the other hand, 31 is a water-cooled heat exchanger similar to the heat exchanger 15 in FIG. 2 provided in the second zone of the cooling zone 1a of the annealing furnace. 32 is a cold water flow path connected to a cold water supply source (not shown), 33 is a cold water flow rate control valve, and 34 is a flow path for hot water after flowing through the heat exchanger, which is used for the hot water washing device 7 and the pickling device S. It is connected to a heat exchanger 35.

36 is a hot water temperature detector, 37 is a temperature transmitter, and 38 is a temperature controller.

Further, 39 is a differential pressure detection valve, 40 is a diaphragm type constant flow regulating valve that operates so that the pressure difference before and after the differential pressure detection valve is constant, and 41 is a bleed-off throttle valve. That is, the hot air obtained by the air-cooled heat exchanger 21 is supplied to the drying devices 3, 5, and 8 as drying hot air, and at this time, even if the strip processing amount changes, the hot air remains at a constant temperature. The temperature controller 27 detects the temperature of the hot air so that
The opening degree of the cold air flow rate control valve 27 is adjusted by.

In addition, since it is necessary to supply a constant flow rate of hot air to each drying device, the supply header pressure is detected and the opening degree of the hot air release valve 30 is adjusted using the pressure regulator 29 to keep the hot air supply pressure constant. hold it. On the other hand, part of the hot water obtained by the water-cooled heat exchanger 31 is supplied to the heat exchanger 35 for heating the pickling liquid of the pickling device 6, and the other part is directly supplied to the hot water washing device r. It is used as hot water for washing. At this time, the hot water temperature is detected and the opening degree of the cold water flow rate control valve 33 is adjusted by the temperature controller 38, so that hot water at a constant temperature is supplied even if the strip processing amount changes, etc. The constant flow regulating valve 40 is operated so that hot water is supplied, and hot water in excess of the required amount is bled off by the throttle valve 41.

In this way, since the cooling heat obtained from the strip in the cooling zone 1a of the annealing furnace 1 is used as a heating source for the front and rear devices of the annealing furnace 1, there is no need to use a special boiler, etc.
Fuel consumption is reduced as well as equipment costs, resulting in significant savings in operating costs.

In this embodiment, a regulating device is provided to maintain constant the temperature of hot air and hot water, the flow rate of supply to the front and rear devices, etc., which is convenient when the load on the AP line, such as the amount of strip processed, fluctuates. If the strip throughput is constant, these regulating devices can be omitted.

Next, we will give a specific example of the effect of this invention, which is the reduction in operating costs.

In a continuous annealing and pickling equipment that processes 8 to 11.5 tons of copper and copper alloy strips per hour, the total amount of hot air required for drying is 300 TrI/pongee of hot air at 65°C, which is
It takes 250,500 Kcal of heat per hour to heat the air.

On the other hand, the required amount of hot water is 601/〒 of hot water at 65℃, and to obtain this by heating water at 20℃, 162,000 K/hour is required.
The amount of heat of ca1 is required. However, since the cooling curve for the minimum throughput of 8 tons/hour is as shown in Figure 4, the cooling heat from the strip is 294,000 Kca1/hour in the first zone and 201,000 Kca1/hour in the second zone. It can be seen that a sufficient amount of heat can be obtained to obtain the hot air and hot water even if heat loss from piping and other sources is considered. Therefore, if the present invention is applied, the total required amount of heat will be 4125 per hour.
Since all the fuel needed to obtain 00Kca1 of heat in the boiler is no longer required, assuming the total thermal efficiency of the boiler and heat exchangers for each front and rear device to be 0.72, it will generate approximately 48.5 kg per hour.
of LPG will be saved and the AP line will run for 7200 hours per year, resulting in a massive fuel savings of 350 tons per year. It is clear that the present invention can also be applied to a continuous annealing and pickling apparatus for metal strips using a horizontal annealing furnace.

In addition, in the present invention, the heat exchanger installed in the cooling zone of the annealing furnace obtains only hot water or only hot air and supplies it to a predetermined device among the annealing furnace and the front and rear devices, depending on the scale and type of the annealing furnace and the front and rear devices. You may also do so.

Further, the heat exchanger may be of the type using convection heat transfer as shown in the above embodiments, or may be of the type using radiant cooling in which radiant heat from the strip is absorbed by a water-cooled or air-cooled tube or chamber. As explained above, according to the present invention, there is no need for a boiler as a heating source for the upstream and downstream devices of the annealing furnace, so equipment costs and operating costs are greatly reduced, and maintenance effort is also reduced.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing a conventional continuous annealing and pickling apparatus for metal strips, Fig. 2 is a horizontal sectional view of the cooling zone of the annealing furnace shown in Fig. 1, and Fig. 3 is a continuous annealing and pickling apparatus for metal strips according to the present invention. FIG. 4, a system diagram showing one embodiment of the apparatus, is an example of a cooling curve of a strip in a cooling zone of an annealing furnace. 1... Annealing furnace, 1a... Cooling zone, 2.
...Degreasing device, 3...Drying device, 4...
...Water cooling tank, 5...Drying device, 6...
... Pickling equipment, 7...Hot water washing equipment, 8...
・Drying device, 17... Strip, 21...
...Air-cooled heat exchanger, 23...Cold air flow rate control valve, 24...Hot air flow path, 27...Temperature controller, 29... Pressure regulator, 30...
Hot air release valve, 31...Water-cooled heat exchanger, 33.
...Cold water flow rate control valve, 34...Hot water flow path, 38...Temperature controller, 40...Constant flow rate control valve.

Claims (1)

[Scope of Claims] 1. A metal strip continuous annealing and pickling apparatus comprising an annealing furnace and equipment before and after the same, such as a degreasing device, a pickling device, a hot water washing device, a drying device, etc., in which a cooling zone of the annealing furnace is provided. A heat exchanger is provided to indirectly cool the strip using a fluid such as water or air as a cooling medium, and a heated fluid obtained by circulating the fluid through the heat exchanger is supplied to a predetermined device among the front and rear devices. 1. A continuous annealing and pickling apparatus for metal strip, characterized by comprising a supply line. 2. In a metal strip continuous annealing and pickling equipment which is equipped with an annealing furnace and equipment before and after the degreasing equipment, a pickling equipment, a hot water washing equipment, a drying equipment, etc., a metal strip continuous annealing and pickling equipment is provided in the cooling zone of the annealing furnace and is equipped with water, air, etc. A heat exchanger is installed in the cooling zone and indirectly cools the strip using a fluid such as water or air as a cooling medium, and a heated fluid obtained by circulating the fluid through the heat exchanger is used in the front and rear devices. The heating fluid is characterized by comprising a supply line for supplying to a predetermined device, a temperature adjustment device for adjusting the temperature of the heating fluid, and a flow rate adjustment device for adjusting the flow rate of the heating fluid supplied to the front and rear devices. Metal strip continuous annealing and pickling equipment.