CN101250601A

CN101250601A - Pre-heating technique of blast furnace before blowing coal powder

Info

Publication number: CN101250601A
Application number: CNA2008100546180A
Authority: CN
Inventors: 刘仁生; 王宏强; 刘新斌; 房连增
Original assignee: Changzhi City Fang Sheng Injection Technology Co Ltd; Shanxi Luan Mining Group Co Ltd
Current assignee: Changzhi City Fang Sheng Injection Technology Co Ltd; Shanxi Luan Mining Group Co Ltd
Priority date: 2008-03-07
Filing date: 2008-03-07
Publication date: 2008-08-27
Anticipated expiration: 2028-03-07
Also published as: CN100535127C

Abstract

The invention relates to a matching technology in blast furnace iron-smelting process for metallurgical industry, in particular to a preheating technology before a blast furnace sprays coal powder, which solves the problem of the realization of coal powder preheating spraying technology in industry. A preheating technology before the blast furnace sprays coal powder heats up coal powder to 120-160 DEG C with the blast furnace high temperature waste gas which is produced by a blast furnace hot blast stove before coal powder is sprayed into the blast furnace, thereby largely reducing the time of coal powder from heating up in a blast furnace air opening to firing, and increasing the combustion time of coal powder in the air opening and a convolution region, thereby increasing the combustion rate of coal powder, reducing the unfavorable affects of the non combusted coal powder for the blast furnace, increasing coal-to-coke replacement, and enlarging coal spraying quantity.

Description

Pre-heating technique of blast furnace before blowing coal powder

Technical field

The present invention relates to the process matched therewith in a kind of blast furnace ironmaking process of metallurgy industry, be specially a kind of pre-heating technique of blast furnace before blowing coal powder.

Background technology

The blast furnace blowing technology is that the levigated coal dust is directly sprayed into blast furnace, with alternate resources poorness, expensive metallurgical coke, play heat-generating agent and reductive agent, thereby reduce coke ratio and pig iron cost, be the burnt volume increase of iron and steel enterprise joint and improve one of effective measures of smelting technology that it is that blast-furnace smelting by fuel injection forms that the pig iron more than 90% is arranged approximately.

But raising along with the winding-up amount, after the coal powder injection ratio is increased to certain limit, the amplitude that coke ratio reduces can significantly reduce, major cause is that the coal dust that sprays into can not perfect combustion before the air port, and the coal gas that unburned coal powder can be risen is taken the district of circling round out of, is attached in the first slag during to the slagging band, increased the viscosity of first slagging, worsen permeability of stock column, make smooth operation of furnace unfavorable, even have the part carbon granule to be taken out of stove to slattern outward.Therefore, how to improve the rate of combustion of coal dust before the air port, become coal powder injection than the key that further improves.The researchist has adopted multiple technologies to improve the combustionproperty of coal dust both at home and abroad, as improving oxygen enrichment percentage, raising wind-warm syndrome, interpolation ignition dope, change coal powder size etc., abovementioned technology is selected to adopt according to self equipment and production technology characteristic by each iron and steel enterprise.

The pulverized coal preheating injection technology is the advanced subject of present injection coal technical field, compares with other technology, and its outstanding feature is to utilize the blast funnace hot blast stove waste gas residual heat to heat coal dust, improves coal combustion rate.Also actively developing this research work both at home and abroad, Brazil Eseola de Minas-UFOP company has carried out three kinds of coal dust mixed injections and coal dust has been carried out the test that preheating (250 ℃) is jetted on the experimental installation in the analog blast furnace air port of its exploitation, test shows that coal dust is carried out preheating can reach higher rate of combustion.

Introduced the said firm in " the coal powder injection operation of TKS's blast furnace " of 2006 the 2nd phases " Anshan iron and steel plant technology " publication and once on industrial blast furnace, carried out the preheating winding-up test of coal dust, but process unit and the working method used have not been made reports.Proposed the pulverized coal preheating winding-up in " preheating is to the volatile influence of mixed coal powder " of " China the is metallurgical " publication of the 6th phase of June in 2007 and helped alleviating the cooling effect of coal powder injection, quickened the combustion processes of coal dust, improved the coal dust utilization ratio hot blast.The document has been inquired into preheating to the volatile influence of mixed coal powder from the angle of coal spraying process safety.

From the existing literature data as can be seen, the pulverized coal preheating winding-up still is in the laboratory bench-scale testing stage, how in actual industrial production, a large amount of swiftly flowing coal dusts to be heated in course of conveying, and how to utilize the waste heat of the useless flue gas of blast funnace hot blast stove be key issue and the core technology that solves pulverized coal preheating injection technology industrial applications as the heating thermal source.

Summary of the invention

The present invention provides the technology and the device of preheating before the spray of a kind of pulverized coal injection in blast furnace in order to solve the pulverized coal preheating injection technology in the industrial problem how to realize.

The present invention is realized by following technical scheme, a kind of pre-heating technique of blast furnace before blowing coal powder, be that the high-temp waste gas that produced with blast funnace hot blast stove before coal dust sprays into blast furnace is heated to 120～160 ℃ with coal dust, thereby shorten coal dust significantly and before blast-furnace tuyere, be heated to the time of catching fire, increase coal dust in air port and the combustion time of circling round and distinguishing, thereby improve the rate of combustion of coal dust, reduce the detrimentally affect of unburned coal powder blast furnace, improve coal-to-coke replacement, enlarge injecting coal quantity.

The high-temp waste gas that blast funnace hot blast stove produces is transported to roasting kiln by induced draft fan and used heat pipe and carries out secondary temperature elevation.Flue gas after heating up is sent into interchanger, utilize the latent heat heating working medium steam of high-temperature flue gas, working substance steam after the heating is sent in the coal dust heating tube by vapor uptake, coal dust is heated to 120-160 ℃ step by step by four heating units, the coal dust after the preheating sprays into blast furnace through power transportation pipe and divider.Working medium condensation vapour in the coal dust heating tube is sent into interchanger again through the steam return tube, recycles.

Adopt the pulverized coal preheating technology to compare with the direct injection technology of not preheating of present coal dust, can improve coal combustion rate about 15% under equal wind-warm syndrome and excess oxygen, improve coal powder injection than 20kg/t iron, molten iron per ton reduces coke consumption 18kg, and good economic benefits is arranged.In addition, the coal dust after the preheating is mobile to be increased, and helps pipe-line transportation.

The present invention on the basis of experiment in conjunction with the on-the-spot actual design of blast furnace special-purpose heating installation and supporting heating process, with industrial scale is that the 1000000 tons of pig iron/years are example, by adopting the present invention pulverized coal injection can be brought up to 150kg/t iron than from current 130kg/t iron, ton iron is saved the about 18kg of coke, ton iron cost reduces about 18 yuan, about 1,800 ten thousand yuan of year benefit.In addition, the annual recyclable waste heat 3 * 10 that utilizes ⁷MJ is equivalent to the annual 1000 tons of standard coals that reclaim.

Description of drawings

Fig. 1 is the preceding pre-heating technique schematic diagram of pulverized coal injection into blast furna spray

Fig. 2 is multistage sectional type coal dust heating pipe structure synoptic diagram

Fig. 3 is the B-B sectional view of Fig. 2

Fig. 4 is that the A of Fig. 2 is to view

Among the figure: 1-power transportation pipe, the multistage sectional type heating of 2-transfer lime, 3-vapor uptake, 4-steam return tube, 5-roasting kiln, 6-used heat pipe, 7-blast furnace gas pipe, 8-interchanger, 9-joint flange, the import of 10-medium, 11-transfer lime, 12-heating tube, the 13-media outlet, the 14-expansion joint, 15-regulates gate valve, the 16-pressure transmitter, the 17-temperature sensing

Embodiment

A kind of pre-heating technique of blast furnace before blowing coal powder, it is characterized in that before coal dust enters blast-furnace roasting, coal dust being heated to 120～160 ℃, use attached heating unit illustrated in Figure 1, this device comprises multistage sectional type heating transfer lime 2, the roasting kiln 5 that connects used heat pipe 6, be connected with blast furnace gas pipe 7 on the roasting kiln 5, roasting kiln 5 is connected with interchanger 8.As schematically shown in Figure 2, multistage sectional type heating transfer lime, it comprises four heating units that link together, each heating unit is made of the

transfer lime

11 and 12 sockets of outer field heating tube of internal layer, be closed between the two ends of transfer lime 11 and heating tube 12, have medium import 10 and media outlet 13 on the heating tube 12, be provided with joint flange 9 at the heating unit two ends, the middle part is equipped with expansion joint 14, the deflection after being heated with compensation.Medium import 10 on the heating tube 12 and media outlet 13 respectively with interchanger 8 on vapor uptake 3 be connected with steam return tube 4.Each heating unit length is 10m,

The waste gas that blast funnace hot blast stove produces is sent into by induced draft fan and used heat pipe 6 and to be carried out secondary temperature elevation in the roasting kiln 5, and the fuel source of roasting kiln 5 is the blast furnace gas in the blast furnace gas pipe 7, regulates the intensification scope by the unlatching of regulating gate valve 15.Send into interchanger 8 through the exhaust gas of hot-blast stove after the roasting kiln heating, in interchanger 8, realize the heat exchange of waste gas latent heat and working substance steam, high temperature refrigerant steam is transported to heating in the transfer lime 11 by vapor uptake 3, heats step by step by four heating units, and coal dust is heated to 120-160 ℃.Coal dust after the preheating sprays into blast furnace after delivering to the stokehold divider by power transportation pipe 1.Working medium condensation vapour is sent into interchanger by steam return tube 4, recycle.All pipelines all adopt lagging facility in the pulverized coal preheating system, to improve the heat energy utilization rate.

Claims

1, a kind of pre-heating technique of blast furnace before blowing coal powder is characterized in that: the high-temp waste gas that produced with blast funnace hot blast stove before coal dust enters blast-furnace roasting is heated to 120～160 ℃ with coal dust.

2, the employed device of a kind of pre-heating technique of blast furnace before blowing coal powder, it is characterized in that: comprise multistage sectional type heating transfer lime (2), the roasting kiln (5) that connects used heat pipe (6), be connected with blast furnace gas pipe (7) on the roasting kiln (5), roasting kiln (5) is connected with interchanger (8), multistage sectional type heating transfer lime (2), comprise four heating units that link together, each heating unit is made of the transfer lime (11) and outer field heating tube (12) socket of internal layer, be closed between the two ends of transfer lime (11) and heating tube (12), have medium import (10) and media outlet (13) on the heating tube (12), be provided with joint flange (9) at the heating unit two ends, the middle part is equipped with expansion joint (14), the medium import (10) on the heating tube (12) and media outlet (13) respectively with interchanger (8) on vapor uptake (3) be connected with steam return tube (4).