RU2352642C1 - Facility for natural gas supply into blast furnace - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: facility contains blower nozzle, connected to gas pipeline with distribution collector of natural gas by jets through coils of cooling plate section of tuyere area ground, located above iron notch and main gutter of blast furnace. Gas pipeline distribution collector of natural gas by tuyeres is cut in water inlet tube to coil pipe cooling plate section of tuyere area platform. Each of two sections of cooling plate section of tuyere area platform above iron notch is connected to one blower nozzle, nearby to section of cooling plate of tuyere area platform.

EFFECT: coke consumption reduction for cast iron smelting.

3 cl, 4 dwg

Description

The invention relates to ferrous metallurgy, specifically to the equipment of a blast furnace, and can be used in the smelting of cast iron with the injection of natural gas into the furnace through air lances.

Heating natural gas before feeding it into a blast furnace provides a significant reduction in coke consumption for pig iron smelting (A.N. Ramm, Modern Blast Furnace Process. - M.: Metallurgy. - 1980 - p. 228).

A tuyere of a blast furnace is known, in the working channel of which there is a heat-resistant screen, which forms an annular gap with the body for heating natural gas, the annular gap on the side of the snout is closed by a ring directing gas through the recesses in the blast, the ring is located at a distance equal to 1/3 of the working lance channel, at the end of the lance working channel, a thrust ring is fixed to hold the heat-insulating layer placed between the guide and thrust rings.

Gas has a low temperature, which is minus 20 ° C in winter. Entering under the screen, the gas is heated by the blast, reduces the heat loss of the hot blast with the tuyere cooling water (see ed. Certificate of the USSR No. 840116, class C21B 7/16, 1981).

The reason that impedes the achievement of the technical result indicated below is that only the heat of hot blast is used to heat the gas.

Known nozzle tuyere device of a blast furnace containing a steel pipe, which inside is lined with rings of refractory material. The rings have through holes, the longitudinal axis of which is parallel to the longitudinal axis of the nozzle pipe and form channels for the passage of gas along the pipe.

Natural gas passing in the pipe lining channels is heated, heat losses of hot blast through the outer surface of the nozzle pipe are reduced (see RF patent No. 2048528, class C21B 7/16).

The reason that impedes the achievement of the technical result indicated below is that the gas is heated only by the heat of hot blast.

A known method of heating natural gas, carried out by its supply to the cooling cavity of the knee flanges of the tuyere of the tuyere of the blast furnace. The gas heated in each of the two flanges of the knee at 190-210 ° C, enters through the air lance into the furnace, reducing coke consumption (see RF patent No. 2294377, class C21B 5/00, 2007).

The reason that impedes the achievement of the technical result indicated below is that the gas is heated only by the heat of hot blast.

A device is known for supplying natural gas to a blast furnace containing a distribution manifold connected to the hollow flanges of the movable knee of the tuyere device, and for the purpose of heating gas, the hollow flange of the movable knee is connected to the channel for supplying gas to the tuyere (ed. Certificate of the USSR No. 399525, C21B 7/16, 1971). The reason that impedes the achievement of the technical result indicated below is that the gas is heated by the heat of hot blast.

To eliminate brown smoke emissions during the release of pig iron from a blast furnace, suction systems are used, placing shelters above the cast iron notch and the main trench. One of the elements of these shelters are the areas of the tuyere zone with stove refrigerators, water-cooled, which are located above the cast-iron notch and the main groove ([1] - ES Turova "Combating brown smoke emissions in foundries abroad", M., 1992 (overview / institute "Chermetinformatsiya" ser. "Protection of air and water basins from emissions of metallurgical plants", issue 1).

At blast furnace No. 4 (hearth diameter 8.4 m) of the Dofasco plant in Hamilton (Canada), the gas exhaust system from the main cast-iron gutter includes a water-cooled shelter above the cast-iron notch, a water-cooled tuyere service platform, a movable shelter of the main gutter, and a retractable probe, skimmer shelter, movable gas duct, mechanism for moving the shelter of the main gutter, a water-cooled lance service platform, umbrellas above the notch and the skimmer. The movable gas duct must be moved only when repairing the main groove [1, p.4, Fig. 3].

At blast furnace No. 3 of the KATOVITSA metallurgical plant in Poland (hearth diameter 12 m, round foundry, 4 cast iron notches, pig iron production of more than 6,000 tons / day, number of releases up to 20 per day), lance service platforms equipped with heat-resistant plates cooled by water [1, p.6-7, Fig. 4]. The furnace is equipped with small-sized guns and drill machines. Each sub-tuyere platform, 5 m wide, forms a kind of roof above the main trench near the blast furnace, which does not allow gases to rise up around the subdomain. On both sides of the main trough, side suction is installed, extending from the working platform of the subdomain to the tuyere platform. From the side suction gases are diverted to the collector located under the working platform of the foundry. The notch and the main gutter are closed for 5 meters from the sides, above and below. On the front side, an open passage for the entry of a gun or a drill is saved. The first section of the main gutter is thus sheltered, no further gutter covering is provided.

Similar solutions for sealing cast-iron notches (Fig. 1) take place on NLMK blast furnaces with a volume of 3200 m ³ with 4 cast-iron notches No. 6, 5 and furnace No. 4 with a volume of 2000 m ³ with two cast-iron notches.

The claimed invention solves the problem of heating natural gas supplied to the air lance due to heat, which is uselessly lost near the furnace.

EFFECT: heating of natural gas supplied to an air lance with heat emitted by cast iron and slag, which flow from a cast iron notch of a blast furnace, reducing coke consumption for cast iron smelting due to the heat introduced by the heated gas.

The specified technical result is achieved by the use of a device for supplying natural gas to a blast furnace equipped with a tuyere zone with plate coolers, characterized in that it contains an air tuyere connected to the collector of distributing natural gas by tuyeres through coils of the plate cooler section of the tuyere zone located above cast iron taphole and the main trench of the blast furnace.

The features of the claimed device are also:

The gas pipeline from the collector of the distribution of natural gas by tuyeres to the air tuyere is cut into the water supply pipe to the coils of the plate coolers of the tuyere area.

Each of the two sections of the plate coolers of the tuyere zone above the cast-iron notch is connected to one air lance that is closest to the section of the plate refrigerators of the tuyere area.

The drawings show:

Figure 1 - existing device for supplying natural gas to a blast furnace.

Figure 2 - the proposed device for supplying natural gas to a blast furnace.

Figure 3 - plate-refrigerator platform tuyere zone of the blast furnace over a cast iron taphole.

Figure 4 - layout of devices for supplying natural gas to a furnace with four cast iron notches.

Information confirming the possibility of carrying out the invention to obtain the above technical result is as follows.

The existing device (Fig. 1) contains an air lance 1 connected through a swivel joint 2, a check valve 3 with a stationary line for supplying natural gas to the lance distribution manifold 9 (devices included in the stationary line of valves 4, 5, butterfly valve 6, the measuring diaphragm 7, valve 8 is not shown to simplify figure 1. Their placement is shown in figure 2 of the present invention).

The water collector 10 through the valve 11, the pipe 12 is connected to the coils of the refrigerator plate section 13 of the pad 15 of the tuyere zone above the cast iron notch 16, cast iron and slag 17 in the main groove 18, located in the casting yard array 19. From the cast iron and slag in the main trough, having a temperature of 1500-1550 ° C, the heat flux 20 of radiation and convection acts on the refrigerator plates.

The proposed device for supplying natural gas to a blast furnace (figure 2) contains an air lance 1 connected through a swivel joint 2, a check valve 3 with a stationary supply line of natural gas, including valve 4, valve 23, valve 5, throttle valve 6, orifice plate 7, valve 8, collector 9 of the distribution of gas by tuyeres (existing scheme); The stationary gas supply line according to the invention includes: complementing the existing circuit, valve 24, gas pipeline 25 with valve 26, the gas pipeline 25 being cut into the pipe 12 of the existing water pipe to the coils of the refrigerator plates from the water manifold 10. The coils of the refrigerator plate section are connected by a gas pipe 21 to the valve 22 with a valve 22 with the existing stationary gas supply line, the collector 9 is the lance 1. A valve 27 is installed on the existing water outlet 14 from the cooler stoves, cutting off the outlet to a water discharge column (not shown).

Heated gas is supplied with: an air lance above the left section of the stove-coolers and an air lance above their right section (the report of the left and right sections is adopted regarding a cast-iron notch: look at the notch from the side of the foundry).

The proposed device provides cooling of the refrigerator plates with water if the blast furnace operates without blowing in natural gas, and cooling the refrigerator plates with natural gas. In this case, the following operations are performed:

- with the open valve 27 at the outlet 14, close the valve 11, turning off the water supply from the water collector 10 to the coils of the refrigerator plates 13;

- close the valve 4;

- close the gas supply to the manifold 9;

- open the valves 23, 24, 26 on the gas pipeline 25, valve 22 on the gas pipeline 21;

- steam collector route 9 - valve 8, orifice plate 7, throttle valve 6, valve 5, valve 24, gas pipe 21, 25 - pipe 12 - coil coils 13 - valve 27 for 15 minutes (steam pipe to the manifold 9 is not shown )

After steaming, close the valve 27, open the valve 4, close the valve 23, open the gas to the manifold 9. Gas passes along the route of the collector 9, nodes 8, 7, 6, 5 - valve 24 - gas pipeline 25 - pipe 12 - coils of refrigerator stoves 13 - gas pipe 21 - valves 22, 4, check valve 3, swivel 2 - lance 1 - furnace.

When cast iron and slag 17 are released from the cast iron notch 16 from the heat flow 20, the cooler stoves 13 are heated, gas passing through the coil coils of the stoves is heated. During the production of massive slabs (figure 3) accumulate heat. With existing practice on the furnace with a volume of 3200 m ³ per day produce 18-21 release. After each discharge, the main trough is not emptied of pig iron and slag. Therefore, on the plate-coolers 13 acts heat flow 20 and between releases. Typically, letki work in sequence: 1-3-8 hours, 2-4 the next 8 hours, i.e. in the shift, the heated gas enters 4 tuyeres (Fig. 4).

On an oven with a volume of 3200 m ³ with a water flow rate of 6.5 m ³ / h for one section of the refrigerator plates, the temperature difference of the cooling water is 9.6 ° C, 260832 kJ / hour is taken from the stoves of one section.

During the operation of the furnace: production of 6983 t / day, natural gas consumption of 92 m ³ / t of pig iron, blast temperature 1139 ° С, 26.7% О ₂ in blast, gas consumption for one of 32 tuyeres is 836 m ³ / h. When the heat capacity of natural gas is 2.02 kJ / m ³ · deg, the temperature increase of the gas entering the lance of the claimed device is

260832: (836 × 2.02) = 154 ° C.

With a calorific value of coke carbon of 3601 kcal / kg, coke savings from 85% C to 8 tuyeres will be

260832 kJ / hour × 8: (3601 × 4.18): 0.85 = 163.1 kg / hour or

163 × 24: 6983 t / d = 0.56 kg / t of cast iron.

Claims (3)

1. A device for supplying natural gas to a blast furnace equipped with a tuyere zone with plate coolers, characterized in that it contains an air tuyere connected by a gas line to the tuyere distribution of natural gas through the coils of the plate cooler sections of the tuyere zone located above the cast iron notch and the main gutter of the blast furnace. 2. The device according to claim 1, characterized in that the gas pipeline from the collector of the distribution of natural gas by tuyeres to the air tuyere is cut into the pipe for supplying water to the coils of the sections of the plate coolers of the tuyere area. 3. The device according to any one of claims 1 and 2, characterized in that each of the two sections of the plate coolers of the tuyere zone above the cast iron notch is connected to one air lance adjacent to the section of the plate coolers of the tuyere zone.

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