JPS5970703A - Humidification device for blasting to blast furnace - Google Patents

Abstract

PURPOSE:To humidify the air to be blasted to a blast furnace to target moisture without requiring any air compressor and the incidental running cost of the compressor by providing internally a water spray nozzle which atomizes water by steam into a blast main line between a fan and a hot stove. CONSTITUTION:A two-fluid nozzle 2 is provided in a blast main line 1. Pressurized water from a water supply system 3 is supplied through a piping 5 into the nozzle 2. On the other hand, the steam for atomization from a steam supply system 4 is supplied to the nozzle 2. The water supplied to the nozzle 2 is atomized to fine water droplets by the steam similarly supplied to the nozzle and the mists are blown into the cold wind in the main line 1, then the fine water droplets are evaporated by the sensible heat of the cold wind to steam. Said steam humidifies the cold wind together with the above-described steam for atomization to the target moisture of the blast.

Description

[Detailed description of the invention] The present invention relates to a humidifying device for blast furnace air.

In order to stabilize blast furnace operation, the blast furnace air is humidified to adjust the theoretical combustion temperature before the tuyere of the blast furnace, and the amount of hydrogen in the blast furnace is adjusted. It is known that Il-regulates.

Specific methods for humidifying this air include the steam humidification method, which humidifies the cold air in the main air pipe between the blower and the hot air stove, and the steam humidification method, which humidifies the cold air in the main air pipe between the blower and the hot air stove. By blowing room-temperature water 'k''& into fine water particles from the water spray nozzle, the sensible heat of the cool air heated by the adiabatic compression of the blower vaporizes the fine water particles and turns them into water vapor, resulting in humidification. There is a water spray humidification method.

This water spray humidification method uses the sensible heat of cold air heated by a blower to turn fine water particles into water vapor and humidify it. Therefore, the water vapor required by the water vapor humidification method can be saved, and the water vapor required for obtaining water vapor can be saved. This has the advantage that not only can energy be saved, but the temperature of the cold air in front of the hot-blast stove is lowered, improving the thermal efficiency of the hot-blast stove and achieving an energy-saving effect.

The present inventor studied the water spray humidification method and obtained the following results.

(1) The amount of water that can be evaporated and penetrated by water spray in the 9t/m water humidification method depends on the temperature of the cold air. For example, in a small blast furnace,
The blast pressure is low, the cold air temperature is low, and it is not possible to increase the amount of spray water, making it impossible to bring the cold air moisture in front of the hot blast furnace (blast furnace blast moisture) to the target value required for stable operation of the blast furnace. If the amount of moisture that can be humidified by water spray evaporation is insufficient for the above-mentioned target value, it must be dealt with by blowing in steam using the steam humidification method.

For example, target blast furnace humidity 2B, 5'/fir
r? + Atmospheric humidity '7.2 f/ /Nm3 + Air flow rate 1
7501JmF/min.

Blow pressure L 6 Kg/crl + cold air temperature 120℃
, the possible water spray humidification amount is 11.5 bars, and the insufficient humidification amount is 9.8? /Nn? is the amount of steam blown by the steam humidification method.

(2) Water at room temperature is sprayed with a water spray nozzle to form fine water particles, and when humidifying by evaporation with cold wind sensible heat at 1loo~250°C, the water droplet diameter is 100 to improve evaporability.
It needs to be about μ or less.

(3) As a water spray nozzle, for example, a water spray nozzle that atomizes water using only water pressure (hereinafter referred to as a fluid nozzle) [When adopted, the fluid nozzle that generates the fine water droplets described above has a water volume per nozzle. In order to spray a small amount of water, for example 10 to 20 g/Nm, which is the amount humidified by the steam humidification method, tens to hundreds of nozzles are required, and maintenance and inspection of the water spray nozzles becomes complicated.

On the other hand, when a water spray nozzle that atomizes water using gas pressure (hereinafter referred to as a two-fluid nozzle) is used as a water spray nozzle, it is possible to spray a large amount of water into fine water droplets with one nozzle. As 10-20 Kg/cr
When compressed air A is used, a few nozzles are sufficient to spray the amount of 10 to 202β that was humidified by the water vapor humidification method, and maintenance and inspection of the water spray nozzles becomes extremely easy. However, the two-fluid nozzle requires compressed air of 10-20h/ca as the atomization medium, and to obtain such compressed air, a separate air compressor is required, which requires compressor operating costs, and requires steam humidification. This reduces the energy saving effect of the steam production method.

(4) When the amount of water spray evaporation and humidification is insufficient for the blast furnace blast target target humidity as in (1) above, the water vapor for supplementing the blast furnace moisture is used as the water atomization medium in the two-fluid nozzle in (2) above. By effectively utilizing the air as a fuel, it is possible to humidify the blast furnace air to the target humidity at low cost without requiring the air compressor or the operating cost of the compressor.

Furthermore, if the amount of water spray evaporation that can be humidified is insufficient with respect to the target blast furnace blast humidity, - a humidification method in which water spray from a fluid nozzle is used to humidify up to the above possible humidification amount, and the shortage is compensated for by the amount of steam blown through a steam blowing pipe. However, compared to this humidification method, a humidification method that effectively utilizes the water vapor for moisture supplementation by air as a water atomization medium of a two-fluid nozzle is necessary to humidify to the amount that can be humidified by water spray evaporation. This greatly reduces the number of nozzles, making maintenance and inspection of the nozzles extremely easy.

The present invention has been made based on the above-mentioned study results.The gist of the present invention is to provide a blast furnace blower characterized by a water spray nozzle for atomizing water into steam being installed in the main blower pipe between the blower and the hot blast furnace. in the humidifier.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the blast furnace air humidification device of the present invention will be described below with reference to the drawings.

In Figure 1, l is the main air pipe between the blower and the hot air stove, and 2
is a two-fluid nozzle installed inside the blower main pipe l. FIG. 2 is a cross-sectional perspective view of the two-fluid nozzle 2, where 2a is a water passage of the nozzle, 2b is a water atomizing medium passage of the nozzle, 2c is a supply hole for supplying water and gold from passage 2a to passage 2b, and 2d is a tip of the nozzle 2. water spray holes are shown.

In FIG. 1, 3 and 4 are water passages 2a of the two-fluid nozzle 2.
and a water supply system and a water vapor supply system connected to the water atomization medium passage 2b. The water supply system 3 includes a water pipe 5 and a pressure pump 6.
and a flow rate detector 7 on the water piping on the discharge side of the pump 6. Flow control valve 8'fr: arranged. In addition, the water vapor supply system 4 includes a water vapor detection pipe 9 and a flow rate detector 10. A flow control valve 11 is arranged. U 2 is a water flow rate controller that is set as a target value for the upper limit amount of spray water that can be evaporated and determined from the blowing pressure and cold air temperature, and controls the flow rate control valve 8 so that the actual value of the flow rate detector 7 becomes the target value; 13 is a water vapor current calculator that calculates the water vapor flow rate necessary to humidify the target air humidity from the water spray evaporation humidification amount determined from the target air humidity, atmospheric humidity, and the above-mentioned upper limit spray water amount; 14 is the water vapor flow rate mentioned above; The flow rate control valve 11 is adjusted so that the actual measured value of the flow rate detector lO becomes
This is a water vapor amount controller that controls the amount of water vapor.

According to the blast furnace air humidification device configured as described above, the water pressurized by the pressurizing pump 6 is transferred to the detector 7 and the controller 12.
．． The amount of water jetted is controlled to be constant at the upper limit amount by a control system including a regulating valve 8, and is supplied to the two-fluid nozzle 2. On the other hand, the water vapor for serving water is calculated by the calculator 13 [(target air humidity) -
(Atmospheric moisture) - (Upper limit water spray evaporation humidification amount determined from upper limit spray water amount)]. Detector 10. Controller 14. It is controlled by a control system such as a control valve 11 and supplied to the two-fluid nozzle 2.

The water supplied to the two-fluid nozzle 2 is turned into fine water droplets by the similarly supplied water vapor, and blown into the cold air in the blast main pipe 2, and the fine water droplets are evaporated by the sensible heat of the cold air and become water vapor. Humidifies cold air with atomizing water vapor to the target air humidity.

In addition, without configuring an automatic water flow rate control system in the water supply system, the valve opening degree of the flow rate adjustment valve 8 is manually set to a constant value, and the two-fluid nozzle 2
It is also possible to supply water to In this case, even if the opening degree of the valve 8 is constant, if the target air humidity and atmospheric humidity change and the required amount of water vapor changes, the amount of misted ice sprayed from the nozzle 2 into the cold air will change. Taking into account the above changes, the opening of the valve 8 is set so that the amount of water sprayed into the cold air from the nozzle 2 does not exceed the upper limit amount of water sprayed, and in order to prevent drainage from occurring in the main pipe 1. It is necessary to do so.

In addition, the two-fluid nozzle 2 is designed to evaporate water at preferably low atomization steam pressure and spray water pressure within the comparison range of the atomization steam amount and spray ice amount used for target air humidity control. Select one that has the ability to form water droplets with a size of 100 μm or less.

For example, when the cold air temperature is 120℃ and the blowing pressure is 1.6, it is 9/cr.
l + Air flow rate 1750 N? 7Z'/min, atmospheric humidity 7-2 Si'/Nm3゜Target air humidity 28.5
ii'/N77z', required humidification amount 21.3ji'/
N i, water spray evaporable humidification amount (maximum water spray humidification lid J 11.5 y 7N77z, water vapor humidification amount 9.8
In the case of S'/Nm8 (atomization steam amount/spray water amount) ≧0
．． 1, spray water pressure 6.8 / (y / tst + f
Steam pressure for IT lid 6OKg/crrtte 100
Use a two-fluid nozzle capable of producing water droplets smaller than μ.

The amount of sprayed ice per two-piece nozzle is 21t/pi.
Extremely large air flow rate: 1750N771/Ki, water jet humidification amount: 11.5 r/N? 7Z"k Only one nozzle is required to be installed inside the main air pipe 2 for humidification.In addition, for a single fluid nozzle that produces water droplets of 100μ or less at a spray water pressure of 10Kg/m2, 80 nozzles need to be installed inside. There is.

As described above, according to the blast furnace air humidification device of the present invention,
When the amount of moisture that can be evaporated and humidified by water spray evaporation is insufficient for the blast furnace blast target target humidity and water vapor is used to supplement the moisture content, the water vapor for supplementing the blast furnace moisture can be effectively used as a water atomization medium in the two-fluid nozzle. Blast furnace air can be humidified to the target humidity at low cost without requiring an air compressor or compressor operating costs that are required when adopting a two-fluid nozzle. Furthermore, since the device of the present invention uses a two-fluid nozzle as the water spray nozzle, the number of nozzles required can be reduced compared to the case where a single-fluid nozzle is used to humidify to the amount that can be humidified by water spray evaporation. Maintenance and inspection of the nozzle can be greatly reduced and facilitated.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the actual flow side of the blast furnace air humidification device of the present invention, and FIG. 2 is a cross-sectional perspective view of a two-fluid nozzle. 1...Blower main pipe 2...Two-fluid nozzle 3...Water supply system 4...Steam supply system 5...Water piping 9 ... ...Steam piping application person: Nippon Steel Corporation

Claims (1)

[Claims] A humidifying device for blowing air from a blast furnace, characterized in that a water spray nozzle that atomizes water into steam is installed in the main air pipe between the blower and the hot blast furnace.