Summary of the invention
On wide in range meaning, the invention provides a kind of technology, this technology is used for direct melting metal-containing supplying material in direct melting container, and produce the process products of molten metal, slag and tail gas from container, this technology comprises, when this technology operates in the state of the art of aforesaid " maintenance " and " idle running ", by the tail gas pressure of control in the tail gas stream that supplies to the fluidized-bed pretreatment unit, control the pressure in the direct melting container.
More specifically, the invention provides a kind of technology, this technology is used for " thermometal production " state direct melting metal-containing supplying material in direct melting container in technology, and the process products of generation molten metal, slag and tail gas, described direct melting container forms the part of direct melting equipment, and this technology comprises:
(a) according to required given processing condition, in a plurality of state of the art, optionally move described technology, this state of the art comprises " thermometal production " state and " maintenance " and " idle running " state, in " thermometal production " state, melting metal-containing supplying material in container is to produce molten metal, in " maintenance " and " idle running " state, directly keep the molten bath of melting material with molten state in the melting container, and do not producing extra molten metal;
(b) when technology operates in " thermometal production " state, to be divided at least two bursts of tail gas stream from the tail gas that direct melting container discharges, and one tail gas stream supplied to the fluidized-bed pretreatment unit, be fed into the metal-containing supplying material of direct melting container subsequently with pre-treatment, and another burst tail gas stream is supplied to described equipment, to be used as fuel gas;
(c) when technology operates in " maintenance " and " idle running " state of the art, will supply to the fluidized-bed pretreatment unit from the tail gas stream that direct melting container discharges, be fed into the metal-containing supplying material of direct melting container subsequently with fluidisation at least; And
(d) when technology operates in " maintenance " and " idle running " state of the art, by the tail gas pressure of control in the tail gas stream that supplies to the fluidized-bed pretreatment unit, control the pressure in the direct melting container.
Preferably, this technology comprises, in the time of in operating in " thermometal production " state, supplying to described equipment with as the exhaust flow in another burst tail gas stream of fuel gas, controls the pressure in the direct melting container by control.
The present invention is based on this understanding: by the tail gas pressure of control in the tail gas stream that supplies to the fluidized-bed pretreatment unit, be best implemented in the pressure-controlling in " maintenance " and " idle running " state of the art.
The present invention is also based on this understanding: by another the alternative tail gas stream with respect to the tail gas stream that supplies to the fluidized-bed pretreatment unit, realize the pressure-controlling during " thermometal production " state best.
Preferably, described technology comprises: will be at least one tail gas stream act as a fuel gas supply to (i) waste heat recovery unit and (ii) in the stove at least one, described waste heat recovery unit is for generation of the steam that uses in this technology, and described stove is for generation of the warm air air blast of using in this technology.
Preferably, " maintenance " state comprises: warm air air blast or hot oxygen-rich air air blast, solid carbon-containing material and flux are supplied to direct melting container, and do not supply with metal-containing material.
Preferably, " idle running " state comprises: warm air air blast or hot oxygen-rich air air blast are supplied to direct melting container, and do not supply with metal-containing material and solid carbon-containing material.
Preferably, described technology comprises: in the water scrubber in the downstream of pretreatment unit, and cooling and remove microparticle material and soluble gas kind and metallic vapor from the tail gas stream that supplies to the fluidized-bed pretreatment unit.
Preferably, step (d) comprising: when technology operates in " maintenance " and " idle running " state of the art, by opening or closing the tail gas control valve in the washer, the exhaust flow of the washer that controlling flows through describes in aforementioned section, thereby control the pressure in the direct melting container, this washer is called " pressure-controlling washer " hereinafter.
Preferably, step (c) comprising: when technology operates in " maintenance " and " idle running " state of the art, the whole tail gas stream basically that discharge to the major general from direct melting container supply to the fluidized-bed pretreatment unit as tail gas stream, and therefore minimize any tail gas shunting.
In this case, in the stove of the warm air air blast of using for generation of described technology or hot oxygen-rich air air blast, has only insufficient tail gas usually as fuel gas.
Therefore, in this case, described technology comprises: when described technology operates in " maintenance " and " idle running " state of the art, with another fuel gas, supply to the warm air air blast used for generation of described technology or the stove of hot oxygen-rich air air blast such as Sweet natural gas.
Preferably, described technology comprises: when described technology operates in " thermometal production " state, in the water scrubber of the upstream of stove and waste heat recovery unit, cooling and remove microparticle material and soluble gas kind and metallic vapor from another burst tail gas stream.
Preferably, the washer of describing in aforementioned section comprises the exhaust flow control valve.
Preferably, described technology comprises: when the beginning of " maintenance " and " idle running " state of the art, be closed in the valve in the pneumatic scrubber of describing in preceding two sections at least basically.
Preferably, described technology comprises: will supply to waste heat recovery unit from the tail gas of pretreatment unit, as fuel gas, to produce the steam that described technology is used.
Preferably, described technology comprises: during " maintenance " and " idle running " state of the art, a part of tail gas stream that supplies to the fluidized-bed pretreatment unit in the pretreatment unit is carried out recycling.
Preferably, described technology comprises: when described technology operates in " thermometal production " state, with first volumetric flow rate warm air air blast or hot oxygen-rich air air blast are supplied to direct melting container, and when described technology operates in " maintenance " and " idle running " state of the art, with the second lower volumetric flow rate warm air or oxygen-rich air air blast are supplied to direct melting container.
Preferably, described technology comprises: when described technology operates in " thermometal production " state, with the pressure-controlling in the direct melting container to the first pressure set-point, and when described technology operates in " maintenance " and " idle running " state of the art, the pressure-controlling in the direct melting container is arrived lower pressure set-point.
Preferably, described technology comprises: the molten metal temperature of monitoring in the direct melting container during " idle running " state of the art, and as required with fuel gas supply to container and in container combustion fuel gas, to keep the molten metal temperature in the container.
Preferably, described technology comprises: when described technology operates in " idle running " state and described technology is during combustion fuel gas, to reduce the level of the slag in the direct melting container in container.
The present invention also provides a kind of technology for the direct melting equipment of operation, this direct melting equipment has direct melting container and fluidized-bed pretreatment unit, described direct melting container moves under pressure, described fluidized-bed pretreatment unit is used for the metal-containing material that pre-treatment supplies to direct melting container subsequently, described equipment produces the product of molten metal, slag and tail gas, wherein, described technology comprises:
(a) according to required given processing condition, operational outfit optionally in a plurality of state of the art, described state of the art comprises " thermometal production " state and " maintenance " and " idle running " state, in " thermometal production " state, melting metal-containing supplying material in container, with the production molten metal, and in " maintenance " and " idle running " state, in direct melting container with molten state keep melting material the molten bath, and do not produce extra molten metal;
(b) when described equipment operates in " thermometal production " state, to be divided at least two bursts of tail gas stream from the tail gas that direct melting container discharges, and one tail gas stream supplied to the fluidized-bed pretreatment unit, be fed into the metal-containing supplying material of direct melting container subsequently with pre-treatment, and another tail gas stream is supplied to described equipment, to be used as fuel gas;
(c) when described equipment operates in " maintenance " and " idle running " state of the art, will supply to the fluidized-bed pretreatment unit from the tail gas stream that direct melting container discharges, be fed into the metal-containing supplying material of direct melting container subsequently with fluidisation at least; And
(d) when described technology operates in " maintenance " and " idle running " state of the art, by the tail gas pressure of control in the tail gas stream that supplies to the fluidized-bed pretreatment unit, control the pressure in the direct melting container.
In general sense, it is a kind of for direct melting metal-containing supplying material and produce the direct melting equipment of molten metal that the present invention also provides, and this equipment comprises:
(a) fluidized-bed pretreatment unit is used for the pre-treatment metal-containing supplying material;
(b) direct melting container, be used for by producing molten metal in the direct melting of this container through the technology of the metal-containing supplying material of preheating, described technology comprises a plurality of state of the art, and these a plurality of state of the art comprise as " startup " described here, " thermometal production ", " maintenance ", " idle running " and " calm ";
(c) exhaust pipe is used for the tail gas that direct melting container produces is taken away, and the tail gas in the tail gas stream is supplied to pretreatment unit; And
(d) process controller is used for when described technology operates in as " maintenance " described here and " idle running " state of the art, supplies to the tail gas pressure in the tail gas stream of pretreatment unit by control, controls the interior pressure of direct melting container.
More specifically, the invention provides a kind ofly for direct melting metal-containing supplying material and produce the direct melting equipment of molten metal, this equipment comprises:
(a) fluidized-bed pretreatment unit is used for the pre-treatment metal-containing supplying material;
(b) direct melting container, be used for producing molten metal by direct melting in container through the technology of the metal-containing supplying material of preheating, this technology comprises a plurality of state of the art, and these a plurality of state of the art comprise aforesaid " startup ", " thermometal production ", " maintenance ", " idle running " and " calm ";
(c) stove, warm air air blast or the hot oxygen-rich air air blast used for generation of technology;
(d) waste heat recovery unit, the steam of using for generation of this equipment;
(e) exhaust pipe is used for the tail gas that produces in the direct melting container being taken away and tail gas being divided into two bursts of tail gas stream, and wherein one tail gas stream is supplied to pretreatment unit by first pipe section, and another burst tail gas stream is fed into second pipe section; And
(f) process controller is used for when technology operates in aforesaid " maintenance " and " idle running " state of the art, by the tail gas pressure of control in supplying to the tail gas stream of pretreatment unit, controls the pressure in the direct melting container.
Preferably, when process controller can also be worked as technology and operated in as mentioned above in " thermometal production " state, by the tail gas pressure of control in the tail gas stream that supplies to second pipe section, control the pressure in the direct melting container.
Embodiment
Below to the description of the equipment shown in the accompanying drawing based on this situation: according to the HIsmelt technology described in International Application Serial No. PCT/AU96/00197 of the applicant, adopt this equipment to come melting to contain the iron supply material, thereby produce molten pig.Disclosure in the patent specification that this international application comprises is attached to herein by cross reference.
This technology is based on the use of direct melting container 3.
Container 3 is containers of the sort of type described in detail in International Application Serial No. PCT/AU2004/000472 of the applicant and PCT/AU2004/000473.Disclosure in the patent specification that these international applications comprise is attached to herein by cross reference.
Container 3 has: siege, this siege comprise base portion and the side that is formed by refractory brick; Sidewall, this sidewall form from the upwardly extending tube that roughly is cylindricality of the side of siege, and comprise top cylinder portion and doffing portion; Furnace roof; Be positioned at the exhaust pipe 9 on container 3 tops; Be used for discharging continuously from container 3 forehearth 67 of molten metal; And the slag notch that is used for regularly discharging from container 3 slag.
Container 3 is equipped with water-cooled warm air air blast (" HAB ") spray gun 7 and eight water-cooled solid spray guns 5 of downward extension, this warm air air blast spray gun 7 extends into the upper space of container 3, and described solid spray gun 5 downwards and extend internally and pass sidewall and enter in the slag.
In use, container 3 contains the molten pig molten bath.To contain iron supply material (such as powdered iron ore, the steel mill's waste material that contains iron or DRI powder), coal and flux (lime and rhombspar) via solid spray gun 5 and directly inject the molten bath.
Particularly, one group of spray gun 5 is used for injecting supply material and the flux of iron content, and another group spray gun 5 is used for injecting coal and flux.
Spray gun 5 is protected their not influences of receptor 3 interior high temperature by water-cooled.Spray gun 5 is lined with the material of high abrasion usually, is subjected to the wearing and tearing of the gas/solid mixture of high-velocity jet to prevent them.
Contain the iron supply material and carry out pre-treatment by being preheating to 600 to 700 ℃ of temperature in the scope, and before injecting the molten bath in 17 prereduction of fluidized-bed preheater.
Inject at ambient temperature before the molten bath, coal and flux are stored in a series of lock hoppers 25.Via coal drying and grinding equipment 71 coal is fed to lock hopper 25.
The coal that injects liquefies in the molten bath, thereby discharges H
2And CO.These gases are as reductive agent and energy source.Carbon in the coal is dissolved in the molten bath fast.Dissolved carbon and solid carbon produce the CO as reduzate also as reductive agent.The iron content supply material melts of injecting is the molten pig in molten bath, and discharges continuously via forehearth 67.The slag that produces in this process is regularly discharged via the slag notch (not shown).
The iron supply material melts that contains that to inject that takes place in the molten bath is that the related typical reduction reaction of molten pig is thermo-negative reaction.Keeping this process, more specifically keeping the required energy of these thermo-negative reaction is CO and the H that discharges by from the molten bath
2With react and provide being generally the oxygen-rich air that injects under 1200 ℃ the high temperature via HAB spray gun 7.
The energy that discharges from the above-mentioned afterfire reaction in the container top space is transferred to the molten pig molten bath via " zone of transition ", should " zone of transition " be the form in the high turbulence zone of the drop that contains slag and iron above the molten bath.The heat heating that these drops are produced by the afterfire reaction in this zone of transition, and turn back to slag/iron bath, thus energy is transferred to the molten bath.
The hot oxygen-rich air that is injected in the container 3 via HAB spray gun 7 produces in hot blast stove 11 by this way, namely, make oxygen-rich air (nominally the oxygen volume content is 30 to 35%) by stove 11, and to air heating, be responsible for 41 via hot-blast afterwards hot oxygen-rich air is transported to HAB spray gun 7.
The operation of regulating stove 11 is to guarantee having continuous, unbroken hot oxygen-rich air to flow to HAB spray gun 7 in 41 being responsible under constant straight line temperature.
Each stove 11 is according to the repeated sequence operation in a plurality of stages, and these stages comprise heating phase, perfusion phase and heat exchange stage, and the heat exchange stage is than the time segment length of heating phase.
During the heating phase of stove 11, heat stove 11 in the following manner, i.e. burning (a) is from the tail gas through cooling and purification of container 3, and/or (b) optional another fuel gas, such as Sweet natural gas, and (c) combustion gases in the burner assembly (not shown) of stove 11, make products of combustion pass through stove 11 afterwards.
During the heat exchange stage of stove 11, in the charge air flow that will produce to gas blower 31 from the oxygen mix of breathing equipment 29.These oxygen-rich air streams pass through stove 11, and at stove 11 internal heating, thereby be that container 3 produces hot oxygen enrichment charge air flow.These hot oxygen-rich air streams are called as " hot-blast " or " warm air air blast " usually.
The perfusion phase of stove 11 is such stages, that is, one of them stove cuts out substantially, and neither burned tail gas (with other fuel gas, such as Sweet natural gas) heats also not by cooling off with the airflow heat exchange.
The time length of the perfusion phase of given stove 11 is at least and opens and closes the required time quantum of valve, the opening and closing of these valves are that conversion tail gas and hot blast are required, thereby (a) given stove are switched to the heat exchange stage and (b) another stove switched to the heating phase from the heat exchange stage from the heating phase.
In flue gas desulfurization (FGD) system 13, purify the products of combustion that stove 11 discharges in its heat-processed.This FGD removes from products of combustion usually with hydrogen sulfide (H
2S) and sulfurous gas (SO
2) sulphur that exists of form.The tail gas that produces in the container 3 contains sulphur, and is such as will be described below, before tail gas arrives stove 11, can not remove sulphur fully in the tail gas clean-up that carry out in container 3 downstreams.
Before the products of combustion that stove 11 discharged in its heating phase passes through the FGD system, described products of combustion can pass through the heat exchanger (not shown), and, as supplying with before material is fed to the burner of stove 11 in the heating phase tail gas and the combustion gases from the container 3 that cool off and purify are preheated at tail gas that will heating and combustion air.The tail gas of container and combustion air can preheat about 180 ℃ temperature.
Tail gas discharges from container 3 via the exhaust pipe 9 that is positioned at container 3 tops, and tail gas is at first by radiant coolers 15, and this radiant coolers is hereinafter referred to as " tail gas cover ".Usually, tail gas leaves container and enters this tail gas cover under about 1450 ℃ temperature.
Tail gas is cooled in by tail gas cover 15, thereby causes producing in steam drum 35 steam that gathers.This tail gas cover can be United States Patent (USP) 6,585, the tail gas cover of the sort of type of the cooling described in 929 and part cleaning of off-gas.
The tail gas stream of leaving tail gas cover 15 is under about 1000 ℃ temperature, and is divided into two strands of air-flows.
Specifically with reference to Fig. 2, one tail gas stream of leaving tail gas cover 15 includes 55-65% the tail gas from container 3, and this burst tail gas stream is at first by wet type taper washing tower 21.
Washing tower 21 makes the tail gas quenching of flowing through wherein, and gets rid of microparticle material and soluble gaseous species and metallic vapor from flow through tail gas wherein.The temperature of tail gas drops to below 100 ℃ from about 1000 ℃ in washing tower, usually between 65 ℃ to 90 ℃.
Washing tower 21 comprises upper chamber 71, lower chambers 73 and makes upper chamber 71, lower chambers 73 interconnected extend perpendicular pipes 75.Washing tower 21 comprises the tail gas control valve 77 that is positioned at pipe 75 lower ends.This control valve 77 comprises hydraulically operated conical component 79, and this conical component energy vertical movement is to open or close the lower end of pipe 75.Washing tower 21 comprises water-jet 69 in upper chamber 71, and with respect to other water-jet (not shown) of pipe 75 and controlling elements 79 location.Make up water and the recirculated water in washing tower are supplied to water-jet.
77 pairs of flows by the tail gas of washing tower 21 of control valve are controlled.This is to first changeable flow constraint from the tail gas of container 3.Therefore, the pressure in 77 pairs of direct melting containers 3 of control valve is controlled, and in the process of producing molten pig, preferably it is controlled to the gauge pressure of 0.8 bar.
Tail gas from washing tower 21 leaves washing tower 21 via the outlet 81 in the lower chambers 73, and by exhaust gas cooler 23, below this exhaust gas cooler 23 further cooled exhaust gas to 50 ℃, usually between 30 ℃ to 45 ℃, with the moisture from tail gas removal capacity, thereby tail gas can be used as fuel gas.Usually, the tail gas that leaves water cooler has 5% or H still less
2O and be lower than 10mg/Nm
3, be generally 5.0mg/Nm
3The mist amount that contains.
Under the situation of common Metal Production, the tail gas that produces is suitable for use as (a) stove 11 (as mentioned above) and (b) fuel gas in the WHR system 25.In addition, the tail gas through washing and cooling is suitable in dry and grinding equipment 71 coal being carried out drying.
For above purpose, will be divided into three strands of air-flows from the tail gas of gas cooler 23, wherein one air-flow leads to stove 11, and another strand air-flow leads to 25, the three strands of air-flows of WHR system and leads to dry and grinding equipment 71.
Tail gas stream from exhaust gas cooler 23 is the tail gas of relative high-content.The air-flow that leads to WHR system 25 mixes with the tail gas of the cooling by preheater 17 as described below and purification, and the tail gas of this cooling and purification is the tail gas of relative low levels, and this is because in this preheater, by the CO in the tail gas and H
2Carried out prereduction to containing the iron supply material.
As above describe in detail, under common Metal Production situation, the caloric value that the tail gas stream of associating has makes it be suitable for the gaseous combustion that acts as a fuel.
The tail gas stream of associating, additional fuel gas source and the air of (Reference numeral 83 indications among Fig. 1) Sweet natural gas form are fed to WHR system 25, and burning within it.
The tail gas stream of associating is burning by this way in WHR system 25, that is, and and maximized destruction CO, minimized formation NO simultaneously
x
Unite with the tail gas from stove 11 from the tail gas that WHR system 25 discharges, lead to FGD system 13 then.In FGD system 13, remove SO
2, and discharge the exhaust to atmosphere by chimney 45.
Approximately contain another strand air-flow of tail gas of 35-45% volume ratio by being used for containing the fluidized-bed preheater 17 of iron supply material.This preheater 17 is removed moisture from containing the iron supply material, and carries out preheating and prereduction to containing the iron supply material.Tail gas is fluidizing agent in the preheater 17 and the source of energy.
When technology is when producing molten metal, the process controller of equipment is controlled the tail gas stream that flows to preheater 17, thereby (a) tail gas stream is controlled to be greater than minimum flow rate, keeping the fluidized state in the preheater 17, and the temperature that (b) will contain the constant of iron supply material preheater to 600 to 700 ℃ the scope.
The tail gas that discharges from preheater 17 passes through swirler 61, and isolates the dust of carrying secretly from tail gas.
Then, tail gas is by wet type taper washing tower 63, and this washing tower 63 is got rid of microparticle material and soluble gaseous species and metallic vapor from tail gas, and the temperature of tail gas is cooled to below 100 ℃ from 500 ℃ to 200 ℃, usually between 65 ℃ to 90 ℃.
Washing tower 63 is identical with the basic structure of above-mentioned wet type taper washing tower 21.Particularly, this washing tower 63 makes the tail gas quenching of flowing through wherein, and gets rid of microparticle material and soluble gaseous species and metallic vapor from the tail gas that flows through wherein.And, as the situation in the washing tower 21, washing tower 63 comprises the exhaust flow control valve, and this control valve has the hydraulically operated conical component, this conical component can vertical movement opening and closing described valve, thereby the flow of the tail gas by washing tower is controlled.
Then, by exhaust gas cooler 65, this exhaust gas cooler 65 further is cooled to tail gas below 50 ℃ from the tail gas of washing tower 63, and usually between 30 ℃ to 45 ℃, removing the moisture of capacity from tail gas, thereby tail gas can be used as fuel gas.Usually, the tail gas that leaves water cooler has 5% or H still less
2O, and be lower than 10mg/Nm
3, be generally 5.0mg/Nm
3The mist amount that contains.
As mentioned above, unite with the tail gas stream from water cooler 23 then through the tail gas of cooling and purification, and in waste heat recovery (WHR) system 25, be used as fuel gas.
This WHR system 25 comprises:
Thermal oxidizer 37, that is, and burner assembly, and relevant combustion chamber;
WHR unit 39, that is, and boiler;
Steam drum; And
Heat exchanger unit is such as overheated spiral tube and softening water water economizer.
WHR system 25 produces saturation steam.This saturation steam mixes with saturation steam from the steam drum 35 of tail gas cover 15, thereby the overheated spiral tube of WHR system 25 produces superheated vapour from this saturation steam.
The steam generation device of WHR system 25 comprises:
Radiation shielding for the protection of the downstream spiral tube;
Overheated of two-stage (wherein, controlling heat by injecting softening water as required, superheated vapour is maintained 420 ℃ temperature) with desuperheater control piece;
Main evaporator portion comprises three convection current spiral tube modules;
Water economizer portion; And
Sweating room has three modular softening water control pieces.
The steam that produces in WHR system 25 and tail gas cover 15 is used for driving the main air compressor (not shown) of HAB gas blower 31 and breathing equipment 29, remaining steam is by the turbine type alternator, and this turbine type alternator produces the required electric energy of operational outfit.
The turbogenerator system comprises the condensing turbine that is designed to receive superheated vapour.The surface condenser of the ejecta of turbine by under vacuum, moving, and by condensate pump institute is formed condensate pump and deliver to degasifier.
Use tail gas to offset a certain amount of electric energy as the fuel gas in the equipment, the equipment that so just makes substantially can be self-sufficient at concerned power, otherwise this a part of power supply will obtain from external electrical network.
Usually, the burner assembly 37 of WHR system 25 is the tubular carbon steel shell, and its inside is fire-resistant and insulation.
In use, because following a plurality of factors, comprise: (a) produce at the technology run duration and thereby the variation of the tail gas of discharging from container 3, (b) equipment is to the variation of steam demand, (c) can be used for the variation of tail gas of the burner assembly 37 of WHR system 25, this variation is because the competitive demand of 11 pairs of tail gas of stove is caused, (d) variation of 11 pairs of tail gas demands of stove, therefore, the burner assembly 37 of WHR system 25 moves under the situation that the associating exhaust flow from above-mentioned tail gas separated flow changes.
Described process quilt is designed in multiple " state " operation down, and these " states " have different operation conditions during the melting operating period, and these " states " for example comprise following state of the art:
(a) start;
(b) production of thermometal namely, is supplied hot ore, coal, flux and hot-blast;
(c) keep, that is, do not supply hot ore, supply coal and hot-blast;
(d) idle running namely, is not supplied ore and coal, and the fuel gas such as Sweet natural gas is supplied in the supply hot-blast in some cases; And
(e) calm, that is, do not supply ore and coal, do not supply hot-blast yet.
During maintaining condition, the caloric value of tail gas can change between low levels and the relative high-content relatively.Caloric value depends on the speed of supplying with coal in the molten bath and supplies with the speed of warm air air blast in the container 3.These parameter influences carbon content and the CO in the tail gas and the CO in the tail gas
2Content.
During idling conditions, the exhaust gas heat value is relatively low.Usually, have only container 3 (together with the purging nitrogen by 5 supplies of solid spray gun) is arrived in the warm air blast supply, the composition of tail gas just is similar to air.
During idling conditions, the thermometal temperature is monitored, and when needed, will be fed to such as the fuel gas of Sweet natural gas in the headspace of molten metal bath top.This fuel gas burns in the warm air air blast.This helps heating container 3 and molten metal bath.
The burning that fuel gas carries out by this way normally completely, thereby with wherein only provide the idling conditions of warm air air blast to compare to container 3, the caloric value of tail gas can not improve.
When technology was in the idling conditions, before container 3 combust fuel gases, the operator of container can be diverted to minimum level with slag, or even had arranged slag.The slag shunting makes the slag that leaves a certain minimum level in container 3, slag arrange then basically with all slag amount discharge containers.Reduce the level of the slag in the container 3, make metal can be directly heat by burning.Under these situations, slag has played the effect of shackle, and has reduced the heat that metal is subjected to.
In above-mentioned state of the art, the volumetric flow rate of the tail gas that produces in the container 3 is different with caloric value.For example, the flow of tail gas is relative higher during the thermometal production status with caloric value, and relatively low during idling conditions.
In addition, during given state of the art process, the volumetric flow rate of the tail gas that produces in the container 3 and caloric value are also different owing to the variation of operational conditions.For example, during the thermometal production status, operational conditions is understood some and is changed, and these variations will cause the tail gas that produces different on amount and caloric value.
In addition, the volumetric flow rate of the fuel gas that can use of WHR system 25 changed along with the stage of stove 11.Particularly, when stove 11 moved in its perfusion phase, the tail gas separated flow that leads to WHR system 25 had quite high flow.As mentioned above, compare in required tail gas amount of heating phase with stove 11, stove 11 is much lower in the required tail gas amount of its perfusion phase.
In addition, in the different states of technology, the steam of equipment (with electric power) demand is different, thereby the volumetric flow rate of the required fuel gas of WHR system 25 is also different with caloric value.For example, during the thermometal production status, the steam of equipment (and electric power) demand exceeds about 40-60% during than starting state.
In addition, in the different states of technology, the fuel gas demand of stove 11 is different.For example, during the thermometal production status, the amount of required fuel gas will be higher than idling conditions.
In view of this, during at least some state of the art, need and to be fed to the burner assembly 37 of WHR system 25 such as the optional fuel gas of Sweet natural gas (or other fuel gas outside the tail gas), thereby satisfy the steam demand of equipment during the melting operating period.
In addition, in view of this, need to change the flow such as the optional fuel gas of Sweet natural gas (or other fuel gas outside the tail gas) of the burner assembly 37 that is fed to WHR system 25, thereby compensation is from variable flow and the caloric value of the tail gas of container 3, to satisfy the steam demand of equipment during the given state of melting operating period.
In addition, in view of this, under at least some state of the art, need to be fed to the burner assembly of stove 11 such as the optional fuel gas of Sweet natural gas (or other fuel gas), with the compensation flow of tail gas and the variation of caloric value, thereby keep target flow and the target caloric value of the fuel gas that burner assembly uses.
When technology operates in calm, maintenance and the idling conditions, need the optional fuel gas of supply such as Sweet natural gas especially.During these states, the tail gas that flows to stove 11 is completely severed, or has the minimizing of certain degree at least, thereby during these state of the art, need have another fuel gas such as Sweet natural gas to keep stove 11 operations with desired level.
Therefore, the process controller of equipment provides the required flow of fuel gas and caloric value by changing the burner assembly 37 that moves WHR system 25 as the flow of the Sweet natural gas of additional fuel gas with the point of any time in technology.
Therefore, the process controller of equipment also moves the burner assembly 37 of WHR system 25 by the flow that changes air, with the variable flow of counteracting tail gas and Sweet natural gas, thereby guarantee best combustion.
Therefore, the process controller of equipment also by changing the burner assembly that moves stove 11 as the flow of the Sweet natural gas of additional fuel gas, provides the required flow of fuel gas and caloric value with the point of any time in technology.
Therefore, the process controller of equipment also moves the burner assembly of stove 11 by the flow that changes air, with the variable flow of counteracting tail gas and Sweet natural gas, thereby guarantee best combustion.
In addition, reduce in the demand owing to stove 11 inner exhaust gas, thereby before the tail gas that leads to burner assembly 37 increased, the process controller of equipment beginning oblique line formula ground in being generally 30 seconds predetermined amount of time increased the air flow quantity of the burner assembly 37 that leads to WHR system 25.
Similarly, in the increase in demand owing to stove 11 inner exhaust gas, thereby before the tail gas that leads to burner assembly 37 reduced, the process controller of equipment beginning oblique line formula ground in being generally 30 seconds predetermined amount of time reduced the air flow quantity of the burner assembly 37 that leads to WHR system 25.
For point at any time, determine the burner assembly 37 of WHR system 25 and the required gas discharge of burner assembly of stove 11, equipment is important parameters at the exhaust gas heat value of different time points.
Equipment comprises mass spectrograph CV1, CV2 and CV3, and these mass spectrographs are positioned at the selected position of equipment, in order to determine the exhaust gas heat value of these positions.Measured caloric value is handled by the process controller of described equipment, and this is that a part of determining tail gas and the required flow of Sweet natural gas is handled.
Selected position is positioned at the downstream of tail gas cover 15 (CV1), exhaust gas cooler 23 and leads to stove 11 and the upstream (CV2) of the tail gas of WHR system 25 shunting and the downstream (CV3) of preheater 61.
Move above-mentioned technology with the scope of different states and also the pressure-controlling in the container during the different states 3 is had influence.
In addition, maintain fluidized state in order to contain the iron supply material, preheater 17 has a certain minimum gas flow requirement.Control gas flow by preheater 17 by the control valve of the wet type taper washing tower 63 that is positioned at preheater 17 downstreams.
Foregoing description shows, when described explained hereafter molten pig, namely when described technology operates in the thermometal production status, controls container pressure by the control valve 77 of wet type taper washing tower 21.
More specifically, equipment comprises the pressure transmitter P1 that is positioned at tail gas cover 15, and this pressure transmitter is monitored the tail gas pressure that flows through the tail gas cover with continuous form.When technology operated in the thermometal production status, the process controller of equipment was in response to the pressure of monitoring, and the control valve 77 of operation wet type taper washing tower 21, thereby regulates pressure as required, preferably keeps constant container pressure.The time constant of the pilot circuit of control valve 77 is significantly less than the time constant of the pilot circuit of the control valve in the washing tower 63 in preheater 17 downstreams.Therefore, the pressure in control container 3 and control during Metal Production, mainly are that container pressure is controlled with regard to the control between the gas flow of preheater 17.
During other states of technology, especially during maintenance and idling conditions, still be necessary to keep the control to the pressure in the container 3.During these states, such pressure-controlling is to realize by the above-mentioned control valve in the wet type taper washing tower 63 in preheater 17 downstreams rather than by the control valve 77 of wet type taper washing tower 21.
More specifically, when technology operates in these states, the control valve 77 of wet type taper washing tower 21 is closed at least basically, thereby does not have tail gas stream or minimum tail gas stream is only arranged at the most by washing tower 21, enters stove 11 and WHR system 25 then from this source.Therefore, during maintenance and idling conditions, the control valve in the wet type taper washing tower 63 becomes main pressure controller.This has also guaranteed the gas flow by preheater, so that metal-containing material is maintained in the fluidized state.
In addition, when technology became in maintenance and the idling conditions, process controller moved to reduce the flow set point that is fed to the warm air air blast of container 3 from stove 11.The pressure set-point of container also is lowered.Usually, the set-point is reduced to gauge pressure 0.4 bar from gauge pressure 0.8 bar.
During maintenance and idling conditions, a part of tail gas by preheater 17 is recycled, and unites with the tail gas from container 3, thereby helps to keep the fluidization conditions in the preheater 17.
Under windless condition, not to the air blast of container supply warm air.Close the washing tower 63 in preheater 17 downstreams, and all tail gas in the preheater 17 are carried out recycle, thereby move as fluidizing agent.
During maintenance and idling conditions, the warm air blast volume that stove 11 produces reduces.Be no more than top temperature in order to ensure stove 11, and during the thermometal production status, compare to the total energy of stove supplied fuel gas, reduce the total energy to stove 11 supplied fuel gases.Like this, during maintenance and idling conditions, the energy that is input to stove 11 reduces, thereby is complementary with the reduction of the warm air air blast stream that reduces to energy requirement.
Under situation without departing from the spirit and scope of the present invention, can make multiple change to the embodiment of the invention described above.