CN207418781U - Blast furnace pulverized coal spraying system for preventing pulverized coal bunker fire by using system negative pressure - Google Patents

Abstract

The utility model relates to a blast furnace pulverized coal spraying system for preventing fire in a pulverized coal bunker by using system negative pressure, which comprises a pulverized coal mill, a pulverized coal pulse bag collector, a pulverized coal bin and a blowing tank connected in sequence; the pulverized coal There is an external circulation pipe between the warehouse and the ascending pipeline, and a secondary air supply pipe is provided on the top of the pulverized coal warehouse. The pulverized coal drop pipe downstream of the feeder at the bottom of the feeder; a manual cut-off valve is set on the outer circulation pipe, and a pneumatic cut-off valve is set on the secondary air supply pipe near the coal powder bin and the air supply branch of the secondary air supply pipe. The utility model can timely remove the accumulated powder on the roof of the pulverized coal silo, eliminate the potential safety hazards of oxidative spontaneous combustion or even explosion of the pulverized coal, and use the negative pressure generated by the pulverized coal spraying system of the blast furnace to adjust the overflow gas when the pulverized coal silo is loaded. And can prevent the waste of pulverized coal materials.

Description

Blast Furnace Pulverized Coal Spraying System Using System Negative Pressure to Prevent Fires in Pulverized Coal Bunker

technical field

The utility model relates to the technical field of blast furnace pulverized coal production and spraying, in particular to a blast furnace pulverized coal production and spraying system which utilizes system negative pressure to prevent fires in pulverized coal bunkers.

Background technique

The blast furnace pulverized coal injection system equipment used in ironmaking needs to be designed and manufactured in strict accordance with the principle of explosion protection. According to the combustion and flow characteristics of pulverized coal, the pulverized coal explosion test of the pulverized coal industrial boiler system of the Ministry of Metallurgy shows that the usual pulverized coal explosion of no more than 500 liters needs to meet three conditions: ① Sufficient pulverized coal concentration or dust cloud concentration; ② There is Sufficient air or oxygen; ③ There is a fire source or sufficient energy. It can be seen from the explosion test that the concentration of pulverized coal and the content of oxygen in the space are the main parameters affecting the explosion characteristics of pulverized coal. Therefore, the explosion-proof measures of the pulverized-coal bunker are mainly designed to block the explosion and meet these three conditions.

In actual production, the pulverized coal system needs to be adjusted and operated at any time according to the blast furnace conditions. If the pulverized coal bunker preparation system is full, unplanned wind shutdown, and the blast furnace suddenly reduces coal or even stops coal, a large amount of stagnant pulverized coal cannot be sent out. , it will be stored in the tank for a long time, and the stagnant residual pulverized coal remaining in the tank for more than 8h-10h has the danger of compaction, spontaneous combustion and fire. Although an automatic pulverized coal injection system is usually provided at present, it does not have a long-term protection function. It can only be manually operated, and the retained coal powder in the coal powder bin and injection tank is discharged to the outside and then stored in the open air or sent to the upper fine powder tank under pressure, and then blown in with a large amount of nitrogen to reduce the oxygen content. The pulverized coal is wet and hardened, the temperature of the material is lowered, and the oxygen content of the pulverized coal and coke in the tank is prevented from spontaneous combustion. The above measures waste a lot of manpower and material resources and must be resolved immediately.

Contents of the invention

The utility model provides a blast furnace pulverized coal spraying system for preventing fires in pulverized coal bunkers by using the negative pressure of the system, which can timely remove the suspended particle powder remaining on the top of the pulverized coal bunker, eliminate the potential safety hazards of pulverized coal oxidation, spontaneous combustion or even explosion, and utilize The negative pressure generated by the pulverized coal injection system of the blast furnace can adjust the overflow gas when the pulverized coal bin is loaded, and can be sucked into the negative pressure system for recycling to prevent the waste of pulverized coal materials.

In order to achieve the above object, the utility model adopts the following technical solutions to realize:

A blast furnace pulverized coal spraying system that uses system negative pressure to prevent fires in pulverized coal bunkers, including pulverized coal mills, pulverized coal pulse bag collectors, pulverized coal bins and injection tanks connected in sequence; The upper part of the bunker is connected with the coal mill through the ascending pipeline; the injection tank is set under the pulverized coal bunker, and its discharge port is connected to the blast furnace through the pulverized coal conveying main pipe, and is connected to the pulverized coal bunker through the powder return process pipe; the pulverized coal bunker is also Connect the negative pressure fan, and the top of the pulverized coal bin is also equipped with a bag filter; the outer circulation pipe is installed between the pulverized coal bin and the ascending pipeline, and the top of the pulverized coal bin is equipped with a secondary air supply pipe, and the air intake of the secondary air supply pipe The end is connected to the external nitrogen pipeline, and the secondary air supply pipe is connected to the pulverized coal discharge pipe downstream of the feeder at the bottom of the pulverized coal pulse bag collector through the gas supply branch; Pneumatic cut-off valves are respectively set on the air supply pipe and the air supply branch of the secondary air supply pipe.

The elevation angle of the rising pipeline is greater than 35°.

The secondary air supply pipe is arranged obliquely, and the angle between it and the vertical direction is greater than or equal to 45°, and the nitrogen outlet at the bottom of the secondary air supply pipe is located below the outlet of the pulverized coal discharge pipe.

A manual cut-off valve is provided on the ascending pipe section of the powder returning process pipe, and a flexible connection structure is provided between the powder returning process pipe and the pulverized coal bin.

A one-way valve is provided on the exhaust pipe at the tail end of the bag filter.

Compared with the prior art, the beneficial effects of the utility model are:

1) Under the premise of satisfying the production requirements, by adding an external circulation pipe and manually operating the relevant valves, it is possible to adjust the 500 tons of pulverized coal particles suspended on the top of the pulverized coal silo, improve the loading power of the powder silo, and remove the pulverized coal safely and efficiently The powder accumulated on the roof of the warehouse eliminates the potential safety hazards of coal oxidation, spontaneous combustion and even explosion;

2) Utilize the negative pressure generated by the pulverized coal spraying system of the blast furnace to adjust the overflow when the pulverized coal bin is loaded to prevent waste of pulverized coal materials;

3) Realize safe and controllable recycling of materials during online production;

4) Adjust the flow rate of pulverized coal through manual operation, so that the source of danger is under control.

Description of drawings

Fig. 1 is a structural schematic diagram of a blast furnace pulverized coal spraying system for preventing fires in a pulverized coal bunker by utilizing system negative pressure according to the utility model.

In the figure: 1. Coal mill 2. Rising pipeline 3. Pulverized coal pulse bag collector 4. Pulverized coal bin 5. Injection tank 6. Negative pressure fan 7. Bag dust collector 8. External circulation pipe 9. Secondary supplement Air pipe 10. Powder return process pipe

Detailed ways

The specific embodiment of the utility model will be further described below in conjunction with accompanying drawing:

As shown in Figure 1, the blast furnace pulverized coal spraying system for preventing fire in the pulverized coal bunker by using the negative pressure of the system described in the utility model includes a coal mill 1, a pulverized coal pulse bag collector 3, a pulverized coal bunker 4 and Injection tank 5; pulverized coal pulse bag collector 3 is set above the pulverized coal bin 4, and is connected with the coal mill 1 through the ascending pipeline 2; the jetting tank 5 is set under the pulverized coal bin The conveying main pipe is connected with the blast furnace, and is connected with the pulverized coal bin through the powder return process pipe 10 at the same time; An external circulation pipe 8 is set between the ascending pipelines 2, and a secondary air supply pipe 9 is provided on the top of the pulverized coal bin 4. The pulverized coal drop pipe downstream of the feeder at the bottom of the pulverized pulse cloth bag collector 3; the external circulation pipe 8 is equipped with a manual cut-off valve, and the secondary air supply pipe 9 near the pulverized coal bin 4 and the secondary air supply pipe gas supply branch road are respectively Set up a pneumatic shut-off valve.

The elevation angle of the rising pipeline 2 is greater than 35°.

The secondary air supply pipe 9 is arranged obliquely, and its angle with the vertical direction is greater than or equal to 45°, and the nitrogen outlet at the bottom of the secondary air supply pipe 9 is located below the outlet of the pulverized coal discharge pipe.

A manual cut-off valve is provided on the ascending pipe section of the powder returning process pipe 10 , and a flexible connection structure is provided between the powder returning process pipe 10 and the pulverized coal bin 4 .

A one-way valve is provided on the exhaust pipe at the end of the bag filter 7 .

The working principle of the blast furnace pulverized coal injection system for preventing fires in the pulverized coal bunker by using the negative pressure of the system described in the utility model is that the coal that needs to be injected in the ironmaking process is pulverized by the coal mill 1 through the ascending pipeline 2 is sent to the pulverized coal pulse bag collector 3, after separation of gas and powder, the collected pulverized coal is discharged into the pulverized coal bin 4 through the feeder, and then unloaded from the pulverized coal bin 4 into the injection tank 5, and the The tank 5 is conveyed to the blast furnace by pneumatic means. When the pulverized coal bin 4 receives the powder falling from the pulverized coal pulse bag collector 3, and when the injection tank 5 is depressurized and exhausted, and the injection pipeline is blocked and blown back, the gas-powder mixture will enter the pulverized coal bin 4, Separate exhaust is required.

In the past, the gas-powder separation in the pulverized coal bin 4 was realized through the bag filter 7 on the top, and the purified waste gas was discharged directly. But in actual production, because its exhaust volume is small, and it is very easy to block, so the exhaust effect is not good, causes the pulverized coal and oxygen concentration at the top of the pulverized coal bunker 4 to constantly increase.

The utility model adds an external circulation pipe 8, which can lead the excess pulverized coal at the top of the pulverized coal bin 4 into the ascending pipeline 2, thereby reducing the concentration of pulverized coal at the top of the pulverized coal bin 4; The air supply pipe 9 feeds nitrogen into the pulverized coal drop pipe and the pulverized coal bin 4, which not only can reduce the oxygen content, but also can promote the pulverized coal to fall.

A manual cut-off valve is set on the ascending pipe section upstream of the powder return process pipe 10 drawn from the blowing pipe 5 to manually adjust the flow velocity of the pulverized coal to improve the power of pulverized coal feeding.

A one-way valve is provided on the pipe at the end of the bag filter 7 to prevent the external air from entering the pulverized coal bin 4 in reverse flow.

The following examples are carried out on the premise of the technical solution of the utility model, and detailed implementation and specific operation process are provided, but the protection scope of the utility model is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

【Example】

Anshan Iron and Steel Co., Ltd. Bayuquan iron-making pulverized coal injection system consists of two independent injection systems, corresponding to No. 1 blast furnace and No. 2 blast furnace. Each system separately supplies a set of 1200 liter pulverized coal bin 4, which is supplied to 2 groups of 100 cubic meter injection tanks 5, and the 2 injection tanks 5 are used as a group for alternate injection, continuously supplying 36 tuyeres of the blast furnace, providing The pulverized coal is injected and fired, and the pulverized coal is continuously injected from the tuyeres and used to adjust the heat of the blast furnace.

In this embodiment, the blast furnace pulverized coal injection system for preventing fires in the pulverized coal bunker by using system negative pressure is a structural improvement based on the original system, as follows:

1) According to the schematic diagram of the system, install external circulation pipes 8 of ￠159×8 on the rising pipes 2 connecting the four coal mills 1 to the pulverized coal pulse bag collector 3 and about 40 meters above the pulverized coal bin 4 and its bracket.

2) Install DN32 secondary air supply pipes 9 on top of the 2 sets of pulverized coal bins 4, and connect the secondary air supply pipes 9 with the pulverized coal drop pipe through the air supply branch. Pneumatic cut-off valves are respectively arranged on the top, and the amount of nitrogen replenishment in the pulverized coal bin 4 is manually controlled to suppress the oxygen content in the pulverized coal bin 4 .

3) A flexible connection structure is provided on the top of the pulverized coal bin 4 to connect with the pulverized powder return process pipe 10 to prevent vibration and impact caused by air flow conveying materials.

4) The elevation angle of the ascending pipeline 2 is set to be greater than 35°, so as to prevent powder accumulation in some straight pipe sections when the flow rate of pulverized coal is low.

5) The ascending section of each group of powder returning process pipes 8 is equipped with a manual cut-off valve, and the flow velocity of pulverized coal is manually adjusted in a small amount.

The above is only a preferred embodiment of the utility model, but the scope of protection of the utility model is not limited thereto. Any equivalent replacement or change of the new technical solution and its concept should be covered within the protection scope of the present utility model.

Claims (5)

1. using the blast-furnace coal powder system spray system of system negative pressure prevention pulverized coal bin fire, including sequentially connected coal pulverizer, coal dust Pulse bag collector, pulverized coal bin and injection tank；Coal dust pulse bag collector is arranged on above pulverized coal bin, is passed through with coal pulverizer upper Riser road is connected；Injection tank is arranged below pulverized coal bin, and discharge port is connected by coal dust conveying supervisor with blast furnace, while by returning Powder process duct connects pulverized coal bin；In addition pulverized coal bin connects negative-pressure air fan, bag filter is additionally provided at the top of pulverized coal bin；Its feature It is, outer circulating tube is set between the pulverized coal bin and increase in pipeline, secondary air compensating pipe is set at the top of pulverized coal bin, secondary air compensating pipe The external nitrogen pipeline of inlet end connection, secondary air compensating pipe connect coal dust pulse bag collector bottom feed machine by tonifying Qi branch The coal dust material blanking tube in downstream；Artificial stop valve is set on outer circulating tube, close to pulverized coal bin secondary air compensating pipe on and secondary air compensating pipe Tonifying Qi branch road sets pneumatic cut-off valve respectively.

2. the blast-furnace coal powder system according to claim 1 using system negative pressure prevention pulverized coal bin fire sprays system, feature It is, the elevation angle of the increase in pipeline is more than 35 °.

3. the blast-furnace coal powder system according to claim 1 using system negative pressure prevention pulverized coal bin fire sprays system, feature It is, the secondary air compensating pipe is obliquely installed, and is more than or equal to 45 ° with the angle of vertical direction, secondary air compensating bottom of the tube nitrogen Outlet is arranged on the lower section of coal dust material blanking tube outlet.

4. the blast-furnace coal powder system according to claim 1 using system negative pressure prevention pulverized coal bin fire sprays system, feature It is, artificial stop valve is set on the rising pipeline section of the back powder process duct, flexible connection is set between back powder process duct and pulverized coal bin Structure.

5. the blast-furnace coal powder system according to claim 1 using system negative pressure prevention pulverized coal bin fire sprays system, feature It is, check valve is set on the tail end discharge duct of the bag filter.