Writer： admin Time：2021-06-10 00:00 Browse：℃
Ultra-high-speed burner characteristics: ultra-high-speed burner fuel at a very high heat load can complete combustion. Burner combustion chamber volume itself is small, in which the fuel can be substantially complete combustion, so the strength of its high volumetric heat of the combustion chamber. So of Converter flue gas heat recovery technology depth exploration research
Of Converter EXPLORATION RESEARCH flue gas heat recovery technology depth
Currently, steelmaking converter flue gas heat recovery device is widely used in evaporative cooling system, the converter steelmaking utilizing the released heat as a heat source temperature flue gas to generate steam. High consumption of water and energy to bring the high temperature flue gas through the vaporizing furnace flue cooled, the temperature dropped to 900 ℃, then cooled by water, dust, causing a lot of waste heat at the same time, severely restricted the energy step down converter steelmaking improve the level of consumption does not meet the state to promote "the development of recycling economy, energy saving," the basic national policy, so depth study converter flue gas heat recovery device use is necessary. Situation 1 MAGANG converter loss MAGANG conventional flue gas temperature T 3 converters 300, 120 t converter 3, 75 t converter 4, are wet dust removal. In a 120 t converter, for example, when the converter steelmaking furnace overflow port 1400 ~ 1600 ℃ high temperature flue gas containing dust After cooling to evaporative cooling of the flue 800 ~ 900 ℃, then through the purification system, a large number of gas washing by water spraying nozzles Length flue gas cooling, dust, the flue gas temperature to about 70 ℃. Although part of the flue gas waste heat recovered by evaporative cooling of the flue, but the 800 ~ 900 ℃ chimney exit flue gas waste heat of vaporization of the water is directly reduced to about 70 ℃, about 800 ℃ waste heat is lost in this portion, cause environmental pollution, water and energy at the same time cause a lot of waste heat of high consumption, OG traditional systems are to ensure the production and operation of converter gas recovery as a starting point, but there is no key consideration flue gas heat recovery and improvement of energy efficiency severely restricted the lift steelmaking converter process energy consumption levels. 2 exploration domestic enterprises, technology road a domestic steel mills had in its 80 t converter waste heat recovery of industrial test depth, the industrial pilot projects put into operation in April 2016, running 731 continuous furnace, each furnace production of low pressure during operation steam 5.16 t, equivalent to the amount of vapor recovered per ton 54 kg; stable at the boiler outlet temperature 160 ~ 180 ℃, good overall thermal efficiency of the waste heat boiler, to meet the EP (electrostatic precipitator) requirements. The industrial pilot project, there are some flaws, including the following: (1) fouling more serious. Alternatively the boiler furnace using direct evaporative cooling tower LT dust removal system, although the cooling function achieved, but the dust removal function of evaporative cooling towers are neglected, leading to the boiler outlet duct between the dust inlet portion and electrically ESP dust concentration large design increase the amplitude, and the flow rate can not meet pipeline design requirements appropriate industry standards, such that said connecting pipes and ESP inlet serious fouling cases, periodic manual cleaning; (2) a closed system design is unreasonable, in particular waste heat boiler field insulation structure produced using welding, resulting in severe leakage, so that there have been 18 times ESP explosion venting may occur during industrial test apparatus into operation, so that eventually electrostatic precipitator anode plate is deformed seriously. 3 Feasibility Analysis 3.1 a converter cooling flue gas and waste heat recycling without difficulty in turbid circulating water treatment systems and recycling of waste heat converter first aspect, there have been three difficulties: thermal shock, explosion hazards and sticky gray scale. Converter blowing is intermittent, the amount of flue gas temperature and flue gas often be highly volatile, and therefore long-term thermal shock withstand substantial heat recovery device material selection is a major problem. Throughout the steelmaking process, in each furnace cycle occurs multiple air - flue - gas conversion between, CO-containing flue gas mixed with the oxygen-containing explosive conditions at any time are provided, it is difficult to completely eliminate the explosion hazards . Lime powder containing converter dust, moisture in the air will encounter activation of slaked lime powder, flue gas Zaiyu CO2 will react to form limestone, this scale using the general method of cleaning hard Ex. The three difficulty increased a converter flue gas heat recovery equipment design and selection, the operation more difficult to maintain.  3.2 practical application through the practical application of the depth of recycling industrial test of converter waste heat, waste heat boiler think confirmatory test is successful. Preliminary tests proved to be improved in terms of design as long as fouling clean-up, Ash ways and tightness systems, boiler explosion venting risk does not exist, the problem of safe and stable operation can be solved. In a full converter dust removal system, the depth of the waste heat recovery came as cooling measures included, but come back and create more favorable conditions for a ultra-low dust emissions, the implementation of energy-saving technologies optimize the integration of environmental protection to achieve green steel production. 4 Magang rehabilitation programs 4.1 technology and equipment according to the study of the advantages and disadvantages of existing systems and new LT OG system, combined with the depth of demand for converter waste heat recovery, Maanshan Iron and Steel plans to use ultra-low emission depth of a converter waste heat recovery plus a dust system ( "DHE" system), which system includes a boiler flue vaporized + + waste heat recovery boiler depth spray tower scrubber girth + + + dehydration column radial wet electrostatic precipitator, gas purified by the three-way valve , water-sealed gas holder into the check valve for the user, does not have the gas recovery condition through the three-way valve to the ignition chimney emission. + Vaporization heat boiler flue depth recovery boiler to the gas temperature is reduced to about 200 ℃ production of saturated steam used for the production of living; waste heat boiler and the convection heating surface having a rough turning flue dust removal function, the dust particles flowing through the large portion of the collision, and inertial separation effects to settle; coarse dust through the gas entering through the flue fine dust removal system: spray tower scrubber girth + + + dehydration column radial wet electrostatic precipitator, dust emission concentration in the fine dust purification system may reach ≤10 mg / m3, has been able to meet the most stringent existing national environmental emissions requirements that countries in may 2018 launch of the "ultra-low emission steel enterprises reform program of work" requirement for steelmaking emissions. Depth heat recovery boiler flue gas inlet line with exit gas now vaporized flue, the smoke temperature, dust content of flue outlet exactly the same vaporization, mainly waste heat recovery boiler drum depth, the evaporation heating surface segment, economizer cycle the pump body and pipe components. Flue gas through a converter to a conventional evaporative cooling flue cooled down to a temperature of 700 ~ 800 ℃, the dust concentration of about 100 ~ 150 g / m3, and the new access within the depth of the waste heat boiler, waste heat boiler flue gas flowing through depth 5 after cooling stage evaporator heating surface flue less 300 ℃, followed by continued cooling to & lt economizer; 200 ℃, and then into a dust removal system. In the process of cooling the flue gas, the boiler producing saturated steam, the low pressure accumulator evacuation whole plant used for the production of steam pipe. Economizer outlet gas temperature 150 ~ 200 ℃, dust concentration less than 90 g / m3. Economizer flue gases out from the converter is coupled to the spray tower for further cooling and dust collector and a wet flue gas saturated deg.] C to about 70 enters the annular gap scrubber, dehydration column and a wet electrostatic precipitator disposed outside the dust removal plant, The final exhaust gas dust concentration of ≤10 mg / m3. Then about 70 ℃ saturated wet flue gas enters the wet electrostatic precipitator for radial fine dust, to ensure a converter exhaust gas dust concentration ≤10 mg / m3, to achieve ultra-low emissions. A primary converter plant flue dust, induced draft fan and the main emission recovery systems are old Lee. Waste heat boiler and flue depth turning dry ash settling down, in order to facilitate uniform and dust handling systems, using water mixed into the ring turbid turbid circulating water prior OG chute. Spray tower, AGS, a dehydration tower OG turbid sewage into conventional water chute ring. Water in the water seal tank into the wet electrostatic precipitator, and then the sludge is pumped to a conventional system OG Water Treatment System. Spray tower and heat water in the wet electrical dust seal into the tank, sludge is then pumped to a conventional system OG Water Treatment System. 4.2 assistance system (1) and a cleaning system to deal with the boiler ash was evaporated on the heated area ash problems, first of all, the high temperature section of the boiler using an evaporator heating surface heating surface of the light pipe, tube pitch appropriate amplification; Secondly, an appropriate increase in flow through the heating surface the flue gas velocity to achieve the purpose of self-cleaning. Again take efficient in cleaning device that can accompany the process of steelmaking in real time cleaning jobs, cleaning and self-cleaning device with the online conduct boiler cleaning, boiler body using automatic mechanical rapping cleaning devices, this mounting means for cleaning may be achieved in the evaporation pipe convection convection heating surface. Drop evaporator heating surface in the waste heat boiler into the lower dust hopper, the bottom of the hopper is provided fluidizing nitrogen gas nozzle, and then by the star unloading group 2 (provided with a nitrogen seal between cinder valve) crushed into dust valve Circulating Water , and then into the original old OG turbid circulating water through the drain chute seal pot. (2) waste heat boiler blowdown sampling system operation in order to adjust the pH of the water boiler, a certain amount of an agent will be added, with the pot continuous evaporation of water, the concentration of the agent will continue to increase, it is necessary from time to time for samples taken from the boiler water is provided a sampling device. Boiler operation requiring regular discharge deposition temperature and pressure are discharged water saturated soil and water in a high concentration of water in the bottom of the pot boiler, boiler blowdown after cooling to be set down discharge. The system is shared with the existing blowdown evaporative cooling system. 4.3 Device arrangement because the gas generated during BOF contains large amounts of CO.'S, and the dust content of up to 100 ~ 150 g / m3; First, CO gas is flammable, and toxic; secondly, high dust content, easily boiler heating surface fouling. Therefore, the overall depth of the waste heat recovery boiler arrangement easily up and down through type, to ensure smooth flow of the gas, there is no corner, the corner is provided with a nitrogen gas security measures. 5 Conclusion After transformation and innovation, set vaporizing boiler flue flue gas heat recovery boiler depth, flue gas temperature to below 200 ℃, the converter will be further vaporized flue waste heat recovery of flue gas, a subsequent dust removal to meet the temperature requirements simultaneously produce more evaporative cooling flue and the like of saturated steam at 2.5 MPa substance per ton of steel can be more recovered about 50 kg of saturated steam, the steam produced may be incorporated into existing evaporative cooling steam system. While having a waste heat boiler and flue turning coarse dust removal function, the crude is about 40% removal efficiency (outlet concentration ≤90 g / m3), reduce subsequent dust removal system load, but also to create conditions for reducing the emission targets system, ensure that the entire i.e. dust removal system outlet concentration ≤10 mg / m3.
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