Blast funnace hot blast stove afterbody waste gas heat utilization power generation system
Technical field
The utility model relates to exhaust gas utilization, energy recovery field, especially a kind of blast funnace hot blast stove afterbody waste gas heat utilization power generation system.
Background technology
According to the related documents introduction: just had 1350 blast furnaces by the end of China in 2009, greater than 200 in the blast furnace of the above volume of 1000m3: wherein 5000m3 level blast furnace has 2, and 3200m3 level blast furnace has 16, and 2500~2800m3 level blast furnace has 42.
At present waste gas of hot-blast stove flue waste heat recovery is applied to two aspects: drying medium and delivery vehicles thing as the coal injection and pulverization system also can be used as preheating gas and combustion air.Drying medium as pulverized coal preparation system extensively adopts, and saves the coal gas amount of pulverized coal preparation system roasting kiln, has reduced the powder process energy consumption.The interchanger preheating gas is set and combustion air is not yet universal at flue.
The blast temperature that improves blast furnace is a strong technological approaches of BF, consumption reduction, synergy.At present, studying in the world the new technology that realizes high blast temperature, add Electromagnetic Heating technique for blast and hot oxygen enriched blast technology etc. before Pure Oxygen Combustion Technology, the air port such as regenerative combustion technology, high performance fuel, but these technology still are in research and development and industrial experiment stage.
The blast temperature of external blast furnace is generally all more than 1250 ℃.China's Baosteel 4350m3 blast furnace blast temperature has reached 1250 ℃.This mainly relies on the measure of three aspects:: (1) adopts hot tube heat exchanger to realize hot stove producer gas and the two preheatings of combustion air; (2) mix and burnt coke-oven gas; (3) combustion air oxygen enrichment.The blast temperature of domestic other large and medium-sized blast furnace maintains about 1100 ~ 1150 ℃ mostly, and the small blast furnace great majority are in the level about 1050 ℃.
Present stove operation both domestic and external generally all is controlled at the hotblast stove dome temperature on the level that is no more than 1400 ℃, to reduce as far as possible the growing amount of NOx and SOx.This dome temperature guarantees that 1250 ℃ of the long-term wind pushing temperatures of blast furnace are feasible.Therefore many experts think, it is that reasonably it had both reflected the state of the art of Now Domestic external hot air stove, was again that we create conditions through great efforts now and can arrive that the wind-warm syndrome target of China's blast funnace hot blast stove is defined as 1250 ℃.
But the preheating temperature tg of blast furnace gas and combustion air, tk itself are subject to the restriction of hotblast stove funnel temperature and heat pipe working temperature, and generally speaking, tg, tk can only reach the level about 200~220 ℃.
Obviously, under above-mentioned two kinds of restriction conditions, the theoretical combustion temperature t of blast furnace gas reason can not be higher than 1450 ℃.In other words, only rely on hot tube heat exchanger preheating blast furnace gas and combustion air, can make the blast furnace blast temperature break through 1100 ℃ of high pointes under the optimal cases, even reach 1150 ℃ of levels, but realize 1200~1250 ℃ high blast temperature target, it is impossible not adopting other technique means.
Fully burning blast-furnace gas is realized two kinds of process systems of 1250 ℃ of wind pushing temperatures, namely at fully burning blast-furnace gas and not enrichment of coal gas, combustion air not under the condition of oxygen enrichment, adopt two kinds of combination pre-heating technique systems, the wind pushing temperature of blast funnace hot blast stove realization more than 1250 ℃ of large, medium and small type be can make, thereby significant economic benefit and social benefit obtained.
In general, the dome temperature of hotblast stove will be higher than 80~150 ℃ of blast furnace blast temperature, and the furnace temperature coefficient ξ of hotblast stove is 0.92~0.98, also is that the theoretical combustion temperature t reason of blast furnace gas multiply by furnace temperature coefficient ξ, is dome temperature just.If consider that from the most conservative angle the difference of getting dome temperature and blast furnace blast temperature is 150 ℃, the furnace temperature coefficient of hotblast stove gets 0.92, and hotblast stove will be realized 1250 ℃ wind pushing temperature so, and the theoretical combustion temperature of blast furnace gas must reach more than 1522 ℃.
Improve the theoretical combustion temperature of blast furnace gas, can not depend on the low heat value Qd that improves blast furnace gas, because along with the reduction of Ironmaking Coke Ratio, the low heat value Q d of blast furnace gas also reduces greatly.Thereby only depend on the preheating temperature tk that improves combustion air and the preheating temperature tg of coal gas.For security consideration, blast furnace gas should not be preheating to too high temperature, generally is advisable with 200 ℃.Combustion air then can be preheating to the temperature that is higher than more than 400 ℃ in used material allowed band.Theoretical Calculation shows, as Qd=3150 KJ/Nm3, and tg=200 ℃ of blast furnace gas preheating temperature, and during tk=355 ℃ of combustion air preheating temperature, can guarantee that blast furnace obtains 1250 ℃ blast temperature.
In the traditional technology, about 250 ℃ of hotblast stove funnel temperature, this part low-grade heat energy from waste gas is large but because temperature is on the low side, be difficult to directly mate steam generating system, perhaps because supporting afterheat generating system and one-time investment is too high, deficiency in economic performance, this partial heat energy finally enter atmosphere with the sensible heat form of waste gas, cause very large waste.
The utility model content
The purpose of this utility model be provide for the deficiency that solves above-mentioned technology a kind of can be effectively with exhaust gas utilization and produce the blast funnace hot blast stove afterbody waste gas heat utilization power generation system of electric energy.
In order to achieve the above object, the blast funnace hot blast stove afterbody waste gas heat utilization power generation system that the utility model is designed, it mainly comprises blast furnace coal source of the gas and vapor wheel generating set, the blast furnace coal source of the gas passes into the burner of blast funnace hot blast stove by blast furnace gas pipeline, simultaneously be connected with the combustion air pipeline at burner, be provided with preheating cavity in combustion air pipeline outside and blast furnace gas pipeline outside, be provided with the outlet blowing line at blast funnace hot blast stove, the outlet blowing line leads to blast furnace, blast funnace hot blast stove is provided with afterbody waste gas smoke discharging pipe, smoke discharging pipe is connected inlet pipeline with preheating cavity respectively and is connected with waste heat boiler, waste heat boiler is connected with the vapor wheel generating set by superheat steam pipeline, the vapor wheel generating set is connected with waste heat boiler by condensate pipe, is provided with the fume emission mouth at waste heat boiler.The characteristics of this structure are that hotblast stove afterbody waste gas funnel temperature is brought up to about 360 ~ 450 ℃ by traditional about 250 ℃, to guarantee to realize the parameter of about 300 ℃ and above superheat steam temperature of steam turbine import, be about to a kind of low-quality waste gas and be converted to environmental protection and the energy-saving significance that heat utilization power generating system behind the high-quality waste gas has great reality.
Be provided with the first temperature-detecting device and the first variable valve at blast furnace gas pipeline, reach 1250 ℃, guarantee that hotblast stove afterbody waste gas funnel temperature brings up to about 360 ~ 450 ℃ by traditional about 250 ℃ simultaneously to guarantee the hotblast stove blast temperature.
In the combustion air pipeline, be provided with the second temperature-detecting device, reach 1250 ℃ to guarantee the hotblast stove blast temperature.
Outlet blowing line at blast funnace hot blast stove is provided with the 3rd temperature-detecting device and the second variable valve, guarantees that the hotblast stove blast temperature reaches 1250 ℃.
Inlet pipeline at waste heat boiler is provided with the 4th temperature-detecting device, guarantees that hotblast stove afterbody waste gas funnel temperature brings up to about 360 ~ 450 ℃ by traditional about 250 ℃
The method of blast funnace hot blast stove afterbody waste gas heat utilization generating is: the blast furnace coal source of the gas enters in the burner of blast funnace hot blast stove by blast furnace gas pipeline, pass into combustion air by the combustion air pipeline in the burner simultaneously, produce high-temperature flue gas after the burning, by by the outlet blowing line about 1250 ℃ hot blast being passed to blast furnace behind the heat exchanger for hot-blast stove heat-shift; High-temperature flue gas leads to preheating cavity by a smoke-exhaust pipeline part, a part enters waste heat boiler by inlet pipeline, carry out heat exchange in waste heat boiler inside and produce superheated vapour, flue gas is discharged by the fume emission mouth, superheated vapour enters the generating of vapor wheel generating set by superheat steam pipeline, the vapor wheel generating set produces electric energy, and produced simultaneously water of condensation enters waste heat boiler by water of condensation.
The resulting blast funnace hot blast stove afterbody of the utility model waste gas heat utilization power generation system, it passes into the blast furnace coal source of the gas in the burner, the heat that produces after the burning leads to blast furnace, a produced simultaneously flue gas part is given combustion air and blast furnace gas preheating, can reach 1250 ℃ with the blast temperature of guaranteeing blast funnace hot blast stove, another part produces superheated vapour after by the waste heat boiler heat exchange, superheated vapour passes into the generating of vapor wheel generating set and produces electric energy, make the each several part reasonable utilization of energy, avoided waste, improved utilization ratio, remarkable in economical benefits is increased.
Description of drawings
Fig. 1 is structural representation of the present utility model.
Embodiment
The utility model will be further described by reference to the accompanying drawings below by embodiment.
Embodiment 1:
As shown in Figure 1, the blast funnace hot blast stove afterbody waste gas heat utilization power generation system that present embodiment is described, it mainly comprises blast furnace coal source of the gas 1 and vapor wheel generating set 14, blast furnace coal source of the gas 1 passes into the burner 4 of blast funnace hot blast stove 3 by blast furnace gas pipeline 2, simultaneously be connected with combustion air pipeline 6 at burner 4, be provided with preheating cavity 7 in combustion air pipeline 6 outsides, be provided with outlet blowing line 5 at blast funnace hot blast stove 3, outlet blowing line 5 leads to blast furnace, blast funnace hot blast stove 3 is provided with smoke discharging pipe 9, the hotblast stove funnel temperature is brought up to about 360 ~ 450 ℃ by traditional about 250 ℃, smoke discharging pipe 9 is connected with the inlet pipeline 10 that preheating cavity 7 is connected with waste heat boiler respectively, waste heat boiler 11 is connected with vapor wheel generating set 14 by superheat steam pipeline 13, vapor wheel generating set 14 is connected with waste heat boiler 11 by condensate pipe 15, is provided with fume emission mouth 12 at waste heat boiler 11.
Be provided with the first temperature-detecting device 16 and the first variable valve 17 at blast furnace gas pipeline 2.
In combustion air pipeline 6, be provided with the second temperature-detecting device 18.
Outlet blowing line 5 at blast funnace hot blast stove 3 is provided with the 3rd temperature-detecting device 19 and the second variable valve 20.
Inlet pipeline 10 at waste heat boiler 11 is provided with the 4th temperature-detecting device 21.
The method of blast funnace hot blast stove 3 smoke discharging residual heat utilizations generating is: blast furnace coal source of the gas 1 enters in the burner 4 of blast funnace hot blast stove 3 by blast furnace gas pipeline 2, pass into combustion air by combustion air pipeline 6 in the burner 4 simultaneously, produce high-temperature flue gas after the burning, by by outlet blowing line 5 about 1250 ℃ hot blast being passed to blast furnace 8 behind the heat exchanger for hot-blast stove heat-shift; High-temperature flue gas leads to preheating cavity 7 by a smoke-exhaust pipeline part, a part enters waste heat boiler 11 by inlet pipeline 10, carry out heat exchange in waste heat boiler 11 inside and produce superheated vapour, flue gas is discharged by fume emission mouth 12, superheated vapour enters 14 generatings of vapor wheel generating set by superheat steam pipeline 13, vapor wheel generating set 14 produces electric energy, and produced simultaneously water of condensation enters waste heat boiler 11 by water of condensation.
Embodiment: blast furnace coal source of the gas 1 passes into the burner 4 of blast funnace hot blast stove 3, combustion air enters burner 4 by combustion air pipeline 6, produce high-temperature flue gas after the burning, by the blast temperature of outlet in the blowing line 5 behind the heat exchanger for hot-blast stove heat-shift reach ~ 1250 ℃ deliver to blast furnace 8, the smoke discharging pipe 9 of blast funnace hot blast stove 3 is divided into two portions with the flue gas of 360 ~ 450 ℃ of hotblast stove funnel temperatures: part of smoke guarantees that the combustion air preheating temperature reaches tk=355 ℃, the blast furnace gas preheating temperature reaches 200 ℃, to guarantee that blast funnace hot blast stove 3 blast temperatures are brought up to 1250 ℃; Another part hotblast stove funnel temperature is that 360 ~ 450 ℃ flue gas directly passes into waste heat boiler 11, produces superheated vapour, drives 14 generatings of vapor wheel generating set.
For guaranteeing that blast funnace hot blast stove 3 blast temperatures are brought up to 1250 ℃, at hotblast stove outlet blowing line 5 the 3rd temperature-detecting device 19 and the second variable valve 20 are set, at combustion air pipeline 6 the second temperature-detecting device 18 is set, at blast furnace gas pipeline 2 the first temperature-detecting device 16 and the first variable valve 17 are set, inlet pipeline 10 at waste heat boiler 11 arranges the 4th temperature-detecting device 21, control the first variable valve 17 with this flue-gas temperature as regulating parameter, reach fuel metering amount and control blast funnace hot blast stove 3 blast temperatures, the purpose of control waste heat boiler 11 input gas temperatures.
When the cigarette temperature on hotblast stove blast temperature and waste heat boiler 11 inlet pipelines 10 is lower than respectively about 1250 ℃ and about 340 ℃, the first variable valve 17 is opened greatly automatically, guarantee the hotblast stove blast temperature reach 1250 ℃, waste heat boiler 11 import flue gases and reach ~ 350 ℃.
After ~ 350 ℃ of flue gases enter waste heat boiler 11, produce superheated vapour (about 1.6MPa, 320 ℃), realized that low-temp low-pressure superheated steam generation, generating efficiency improve, remarkable in economical benefits increases.
The designed operation regulative mode of the utility model is:
At waste heat boiler 11 inlet pipelines 10 the 4th temperature-detecting device 21 is set, controls the first variable valve 17 with this flue-gas temperature as regulating parameter, reach the purpose of fuel metering amount and control waste heat boiler 11 input gas temperatures.