AT12170U1 - METHOD AND DEVICE FOR DRY DUST REMOVING AND CLEANING GAS PRODUCED IN IRON PRODUCTION OR COAL GASIFICATION - Google Patents

Description

Austrian Patent Office AT12170U1 2011-12-15

description

METHOD AND DEVICE FOR DRY DUSTING AND DRY CLEANING OF DUST AND DAMAGED GAS, SUCH AS GAS CAUGHT IN RAWING MACHINERY IN IRON PRODUCTION OR IRON PRODUCTION AGGREGATES IN IRON PRODUCTION OR GAS PRODUCED IN COAL GASIFICATION PLANTS

The invention relates to a method for dry dedusting and dry cleaning of dust and polluted gas, such as produced in pig iron production units in the production of pig iron or iron production aggregates in the production of iron gas or gas produced in coal gasification, and an apparatus for performing the method.

In the production of pig iron in pig iron production units, such as blast furnace, COREX® plant, FINEX® plant, melter gasifier, or the iron production in iron production units, such as MIDREX® systems, HYL® systems, direct reduction (DR) systems based on COREX® / FINEX® export gas, large quantities of gases are produced. These gases carry a large load of dust with large amounts of fine solid particles and a variety of gaseous pollutants with it. Especially in unsteady operation, so special operating situations such as start or stop the pig iron or iron production process or spontaneous process anomalies, such as spontaneous slippage of the material column in the aggregates, it can lead to particularly high dust and pollutant loads of gases and peaks of the gas temperature come. Before discharging the gases into the environment or their use in downstream processes, the dust must be separated and the gas purified from pollutants.

By way of example, the properties of the resulting in the production of pig iron in blast furnace, COREX® plant, or FINEX® system gases are shown:

Blast furnace COREX® FINEX® gas volume tr. [Nm3 / h] 350.000-750.000 250.000 - 400.000 150.000-350.000 Gas temperature [Ό] 100-200; max 800 300; max 600 400-450; max 600 gas pressure [kPa] 250; max 350 320 220-320; max 600 gas composition [vol%] CO 20-25 35-40 20-25; max 75 CM OO 20-22 30-35 30-35 h2 2-4 15-20 10-15 n2 50-55 10-15 15-20 Dust loading [mg / Nm3] In the resulting gas 20,000 - 25,000 20,000 - 25,000 12,000- 37,000 pollutants in the resulting gas [mg / Nm3] HCl HF H2S BTX PAH 0.4 0.1 70-100 150 40; max 140 7 <0.2 30-100 150 40, max. 300 1/12 Austrian Patent Office AT12170U1 2011-12-15 It is known to liberate the resulting gas by means of wet process of dust and pollutants, but such methods raise the problem of having to recycle accumulating sludge and wash water.

In the Chinese patent application CN1818080 a process for the dry dedusting of a blast furnace-derived gas stream is disclosed. In this case, after a dry preliminary separation in a separation chamber, the gas stream is subjected to a dry dedusting by means of filtering separators. In operating situations outside the stationary operation of the blast furnace, for example when starting or stopping, or at exhaust gas temperatures below the water or acid dew point of the moisture contained in the gas stream, however, the problem in such methods, the fact that the filter material of the separator glued and clogged, because condense in the gas entrained compounds, such as aqueous moisture or organic compounds. This leads to a considerable pressure loss on the filter material as well as loss of the filter effect and may necessitate the replacement of the filter material with associated downtime. If the device in which the dedusting is carried out is not available because of such problems, the dust-laden gas must be released into the environment via bypass without further purification. Such bypass situations pollute the environment and are not allowed in many industrialized countries.

In order to reduce the risk of sticking or clogging due to dew point undershooting the gas temperature and associated condensations, heat exchangers are provided in CN1818080, which are traversed in the case of too low a temperature of the pre-separation leaving the gas stream and raise the gas temperature above the dew points. Measures for cleaning the exhaust gas of pollutants are not taken in CN1818080.

The present invention has as its object to provide for the resulting in pig iron production exhaust gas a process for dry dedusting, in which reduces the risk of sticking and clogging of the filter for dedusting and at the same time the exhaust gas is cleaned of pollutants. Likewise, an apparatus for carrying out the method is to be provided.

This object is achieved by a method for dry dedusting and dry cleaning of dust and polluted gas, such as in pig iron production units in the production of pig iron or iron production aggregates in the production of iron gas accumulating or gas produced in coal gasification, in which an existing from this gas After a pre-separation for the deposition of coarse solid particles, the gas stream is subjected to dedusting, in which dedusting the solid particles contained in the gas stream, optionally already subjected to the preseparation, are separated from the gas stream, and the temperature of the gas stream prior to dedusting is adjusted so that its temperature is above 60 ° C, preferably above 100 ° C, and less than a damage to the dedusting carrying devices causing temperature.

The inventive method is characterized in that the gas stream before the dedusting additive is added, wherein the additive contains reagent and optionally adsorbent.

A pig iron production unit may for example be a blast furnace, a reduction shaft or melter gasifier according to COREX® or FINEX® process. In such aggregates, solid or liquid pig iron or steel precursor is produced.

An iron-producing unit may be, for example, a MIDREX®, a HYL® plant or a COREX® / FINEX® export gas-based direct reduction plant. In such aggregates sponge iron or briquetted iron is produced.

In the optional pre-separation can be carried out the deposition of coarse solid particles, which are carried in the gas stream, for example, in gravity chambers and 1212 Austrian Patent Office AT12170U1 2011-12-15 (dust bag) or cyclones. Among coarse solid particles are solid particles having particle diameters &gt; 10 gm to understand. Since the pre-separation effectively separates only coarse solid particles up to the above-mentioned lower limit of the order of magnitude, these lower limit sub-boundary solid particles are still present in the gas flow. Such solid particles including particulate matter &lt; 2.5 gm and, if no pre-separation is carried out, even coarse solid particles are used in dedusting down to dust concentrations &lt; 5 mg / Nm3 removed from the gas stream.

If a pre-separation exists, the adjustment of the temperature of the gas stream before dedusting according to an embodiment of the method according to the invention after the pre-separation.

The temperature of the gas in the production of pig iron or iron production varies, for example, depending on the method used, or depending on the occurrence of unsteady states of the process, such as collapse of a column of material in the reduction or meltdown shaft, starting and Abfahrsituation.

The dedusting takes place in filtering devices such as fabric filters made of glass or synthetic fiber such as Aramid® or P84® (polyimide fiber) in round design, metal or ceramic filters.

In order to protect the devices in which the dedusting is carried out before condensation problems that cause sticking of the deposited during dedusting filter cake, and temperature peaks of the gas stream, the temperature of the gas stream before dedusting, after any pre-separation set such that the temperature of the dedusted gas stream is above 60 ° C, preferably above 100 ° C, and less than a temperature causing damage to the dedusting devices. In the case of fabric filters, the temperature must be below 260 ° C., preferably below 200 ° C., since fabric filters suffer heat-induced decomposition of the filter fabric at gas temperatures above 260 ° C. In the case of ceramic or metal filters, gas temperatures up to ΙΟΟΟ'Ό can be used.

In the production of pig iron in pig iron production units or in iron production in iron production aggregates resulting gas contains, inter alia, hydrogen sulfide, hydrogen chloride, hydrogen fluoride, heavy metals, organic pollutants such as Dioxi-ne / furans, polycyclic aromatics and other hydrocarbon compounds. These environmentally harmful exhaust gas components are to be removed as economically feasible before discharge of the exhaust gas into the environment.

According to the invention, the gas stream before the dedusting additive is added as a particulate dry additive or as a suspension of additive in water. The additive contains reagent and optionally adsorbent.

The reagent is selected so that it reacts with the pollutants contained in the exhaust gas from pig iron to particulate products, which are removable by dedusting from the gas stream. The reagent used is, for example, CaCO 3, Ca (OFI) 2, Mg (OFI) 2, sodium bicarbonate, or mixtures of two or more of these substances. The main purpose of the reagent is to deposit acidic pollutant components such as H2S, FICI or HF.

The additive may also contain organic and / or inorganic adsorbents, for example Flerdofenkoks (FIOK), activated carbon / coke or finely ground zeolite. By the adsorbent pollutants contained in the exhaust gas, such as heavy metals or organic pollutants can be removed by adsorption from the gas stream, wherein the product resulting from adsorption of particulates laden with pollutants is particulate and therefore also in the dedusting from the gas stream is removable.

The additive may also be a lime-coal mixture with additives, as it is known for example under the brand name Sorbalit®.

The particulate additive or particulate reaction products or particulate adsorptively laden additive constituents are again removed from the gas stream during dedusting.

The additive can also be injected as a suspension in water, such as milk of lime, in the gas stream. For the addition in suspension, a correspondingly high gas temperature> 150 ° C is required. If additive is added as a suspension in the gas stream, the liquid evaporates in the hot gas stream, so that the additive is removable as a particulate dry additive by dedusting.

Since gas cooling takes place during the addition as a suspension, this type of addition can be coupled with process steps for adjusting the gas temperature.

The addition of additive according to the invention has the advantage that contained in the gas pollutants are removable simultaneously with the dedusting of the gas stream. Another advantage is that both reagent and adsorbent can bind moisture contained in the gas stream and thus reduce the risk of moisture condensation from the gas stream.

In addition, it is advantageous that the additive, or the particulate products formed on the adsorbent in the case of reaction with reagent or adsorption, is deposited on the filtering and separating devices for dedusting and, as a result, coating of these devices takes place. This coating of deposited filter cake containing additive on the one hand contributes to dedusting, since the gas flow must pass through them. On the other hand, it protects the filtering and separating system parts of the devices for dedusting, since the exhaust gas stream meets only after the coating has been passed through. The risk of clogging or sticking of the filtering and depositing system parts of the devices for dedusting is reduced because organic gaseous ingredients of the gas stream or moisture and / or fine adhesive solid particles can be partially already deposited in the filter cake. The resulting protection of the system components results in extended service life.

The coating by the additive is periodically removed together with the filter cake of dust which forms in the course of dedusting on the filtering and separating components of the devices for dedusting; this removal is less complicated and difficult than the removal of solid particles which have penetrated into the filtering and separating components of the devices for dedusting.

According to one embodiment, the addition of additive is carried out as a function of the load of the gas with pollutants. In this case, the content of pollutants is measured and a corresponding addition of additive triggered or increased when the operator predefined thresholds in Rohbeziehungsweise pure gas are exceeded. Here, raw gas is to be understood as the gas before dry cleaning, and gas under clean gas after dry cleaning. It is preferred that individual types of pollutants can be considered. In a preferred embodiment, the type of reagent in the additive is selected according to the pollutant being considered. Thus, the optimally suitable for the relevant pollutant reagent can be added. Accordingly, the costs for reagent consumption can be minimized and the resulting amounts of solid particles deposited in the dedusting can be reduced. A corresponding further utilization is thereby facilitated.

If a pre-separation is present, the gas stream is added according to an embodiment of the method according to the invention before the start of dedusting after the pre-separation additive. This avoids the removal of additive from the gas stream before dedusting. Otherwise, the residence time of the additive in the gas stream would be reduced compared to a separation in the dedusting and accordingly the cleaning capacity of the additive are less well utilized. Since the addition of additive into the gas stream takes place only after the pre-separation, the material obtained in the pre-separation contains no additive. Due to the absence of additive, it is particularly well suited to be used for a purpose. Because the material contains no additive, no consideration must be given to the existing additive in such use. For example, the use may be an at least partial recirculation of the material into the process in which the gas to be purified is produced. It can also be used in other processes.

When the gas to be purified is obtained in pig ironmaking plants or in ironmaking plants in the iron production, the material obtained in the pre-separation contains iron-containing dust - a valuable raw material which can be recycled, for example, back to the pig iron production or iron production. When the gas to be purified is produced in coal gasification plants, the material obtained from the pre-separation contains carbonaceous dust - a valuable raw material which, for example, can be returned to the coal gasification plant.

A pre-separation has the advantage that system parts, which are traversed by the pre-separation of the gas, are less burdened by contact with solid particles.

With the method according to the invention is thus achieved that even in operating conditions such as startup, shutdown or malfunction of the pig iron or ironmaking units, during which the risk of clogging or sticking the filtering and separating acting equipment parts of the dedusting devices due to the danger the condensation is particularly large dust removal compared to the prior art can be performed without interference. Since dedusting and pollutant cleaning can be carried out even in such operating conditions, there is hardly any need to discharge dust and pollutant-laden gas into the environment via a bypass.

According to one embodiment, the additive consists of one or both of the components reagent and adsorbent, because additional constituents of the additive, which do not act as a reagent or adsorbent, reduce the per unit mass additive effect achievable effect of the additive.

Admitted particulate dry additive has a particle size of 0.1 to 200 gm This grain size range ensures that the additive homogeneously distributed in the gas stream. If a significant particle size fraction is concerned, a homogeneous distribution in the gas stream would be difficult, which would lead to low separation rates during dedusting. The smaller the grain size of the additive, the greater its specific surface area. The larger the specific surface area, the better the processes of reaction with and adsorption of pollutants as well as binding of moisture can proceed.

However, the price of the additive increases with decreasing grain size, so that the use of additive having a particle size below 0.1 gm is no longer economically useful.

The exhaust gas from pig iron production units is generally under high pressure. The absolute pressure of the exhaust gases from pig iron production units is between 2 x 105 Pa and 6 x 105 Pa, ie between 2 and 6 bar. This pressure must be overcome when the additive is added to the gas stream. This is preferably done by pneumatic pressure injection of the additive.

Alternatively, the introduction of dry additive can also be done by gravity dosing, in which case a seal of the overpressure to the outside, for example by means of rotary valves or double pendulum valves is to ensure.

When the additive is added to the gas stream, homogeneous distribution of the additive must be ensured. This can be achieved, for example, by a so-called static mixer (with gravity metering) or a corresponding number of injection lances (with pressure injection).

The introduction of suspensions is preferably carried out by two-fluid nozzles, wherein the liquid suspension is atomized by means of gas or steam.

The deposited during dedusting to filtering and depositing devices for dedusting solid particles are removed periodically from these devices. Amongst the deposited solid particles there is also additive, which is still available in the Austrian Patent Office AT12170U1 2011-12-15

Exhaust pollutants can react, adsorb pollutants or bind moisture.

Therefore, according to one embodiment of the method according to the invention, a partial amount of the solid particles separated off during the dedusting as a filter cake is added to the gas stream before the dedusting begins, after completion of the optional pre-separation. This recirculation of additive into the gas stream increases the effect achievable per unit of quantity of additive, since after the first addition of an amount of additive additive unused reaction, adsorption and moisture binding potentials can be used after the renewed addition to the gas stream. Thus, compared to a process without recycling the same effect can be achieved with less fresh additive, which automatically reduces the amount of auszuschleusendem filter cake.

The addition is due to the exhaust gas pressure, preferably by means of pneumatic pressure injection, but can also be done for example by means of gravity dosing.

Carbon particles such as coal dust, hearth furnace coke HOK, sorbalit®, and ore-containing dust and iron-containing dust are also present under the solid particles deposited by the filtering and separating devices for dedusting.

In order to use this material in pig iron production or iron production or coal gasification, according to an advantageous embodiment of the method according to the invention at least a subset of deposited in the pre-separation and / or dedusting as a filter cake solid particles as starting material for pig iron production or iron production or gas produced in coal gasification used. This improves their efficiency and utilizes the separated solid particles in a simpler manner than it would a landfill. However, the material can also be utilized, for example, after any pretreatment steps in the steelmaking process (converter, electric furnace) or the sintering process.

The adjustment of the temperature of the dedusting gas stream is carried out according to an embodiment of the method according to the invention by means of evaporative cooler. This has the advantage that the temperature can be stably stabilized to a set temperature for longer periods of time.

According to another embodiment of the method according to the invention, the temperature adjustment takes place by means of plate heat exchanger. This has the advantage that no additional water injection must be provided and the average gas temperature or the sensible heat of the gas is higher. This increases, for example, the energy efficiency of a downstream use in a Gasentspannungssturbine against a temperature setting by evaporative coolers.

There are generally two variants. Either the gas is passed over the heat accumulator only when the maximum operating temperature of the devices carrying out dedusting, for example 260 ° C., is exceeded and, if the temperature falls below it, passed past it again, or else two plate heat exchangers are connected in parallel. If the outlet temperature of one heat accumulator exceeds the maximum operating temperature, it is switched over to the other, in the meantime the hot accumulator, for example, being recooled with ambient air.

Coal gasification plants, which may be applied for example as a fixed-bed gasifier or as entrained flow gasifier, produce a gas which is comparable in its properties, especially with regard to dust and pollutant load, with gas from pig iron and iron production units. Gas from coal gasification plants is used, among other things, in the production of pig iron or iron as a reducing gas. According to one embodiment of the method according to the invention, the gas to be subjected to the dry dedusting and dry cleaning originates from a coal gasification plant.

To carry out the method according to the invention, a device with a gas flow from a pig iron production unit or an iron-making unit or a coal gasification plant leading supply line, in which a pre-separation is AT12 170U1 2011-12-15

Device is present, wherein the supply line branches at a branch in a bypass line and in a primary gas line, with at least one dedusting device, wherein the primary gas line is connected via a connecting line with the dedusting, and wherein before the dedusting device in the supply line or the primary gas line, a device to adjust the temperature of the gas stream is present.

This device is characterized in that there is a device for adding additive in the primary gas line, wherein the device for adding additive is located between the branch and the first connection line seen from the branch.

The pig iron production unit whose exhaust gas is to be cleaned and dedusted may be, for example, a blast furnace, a reduction shaft or melter gasifier according to COREX® or FINEX® process.

An iron-producing unit can be, for example, a MIDREX®, a HYL® plant or a COREX® / FINEX® export gas-based direct reduction plant.

The feed line leading a gas stream from a pig iron producing aggregate or an ironmaking aggregate is connected to the pig ironmaking aggregate or ironmaking aggregate.

The pre-separation device comprises, for example, gravitational settling chamber, cyclone, hurriclon, electrostatic precipitator. With such devices, coarse particulate matter can be effectively separated from the gas stream.

The dedusting device comprises, for example, round filter with filter bags made of textile fabric, ceramic or metal fabric. With such devices, the finest solid particles &lt; Effectively separate 10 pm from the gas stream.

Such preseparation devices and dedusting devices are capable of operating under the pressure of the gas to be dedusted.

According to one embodiment of the device according to the invention, the device for adjusting the temperature of the gas flow is located between the pre-separation device and the dedusting device.

According to one embodiment of the system according to the invention, the device for adding particulate dry additive is a device for pneumatic pressure injection.

According to another embodiment of the system according to the invention, the device for adding additive is a device for gravity dosing.

According to one embodiment of the device according to the invention, the dedusting device comprises a device for removing separated solid particles.

According to one embodiment of the device according to the invention, the pre-separation device comprises a device for removing separated solid particles from the pre-separation device.

According to a further embodiment of the device according to the invention is based on the device for removing separated solid particles from a solid particle line, which, as seen in the flow direction of the gas stream, or seen from the branch in the bypass line and primary gas line, first connecting line opens into the primary gas line. Advantageously, the mouth is provided with a device for pneumatic pressure injection, by means of which the solid particles can be introduced against the pressure of the gas stream in the primary gas line.

According to a further embodiment of the device according to the invention, the device for removing separated solid particles and / or the device for removing separated solid particles from the preseparating device assumes a supply line which, in a device for adding material to the pig ironmaking unit or the ironmaking unit opens.

According to a further embodiment of the device according to the invention, the device for adjusting the temperature of the gas stream comprises an evaporative cooler.

According to another embodiment of the device according to the invention, the device for adjusting the temperature of the gas stream comprises a plate heat exchanger or other types of heat exchangers such as tube bundles, forced draft cooler, lungs.

According to a further embodiment of the device according to the invention, the device for adjusting the temperature of the gas stream comprises a burner. With a burner, an increase in the temperature of the gas stream above the lower limit of 60 ° C can be achieved quickly - and in general, in terms of apparatus, simply and easily controllable.

The fuel supplied to the burner is a combustible gas or a combustible gas mixture. It is preferred to use at least part of the dry dedusted and dry-cleaned gas obtained in the process according to the invention as fuel for the burner.

According to a further embodiment, the supply line carries a gas stream from a coal gasification plant connected to it.

The present invention also solves the problem of using the energy contained in the gas - for example, to generate electricity in a dedusting and cleaning process downstream turbine, such as an expansion turbine, -, or the components of the gas - for example, in chemical processes - to simplify. Such uses are simplified by the cleaning and dedusting according to the invention, since the system components used for these uses are less exposed to the attacks of solid particles and pollutants, which may, for example, have an abrasive and corrosive effect. In the event that a heating - for example by means of a burner - is necessary to set the temperature of the gas stream, it is advantageous to recover the heat energy supplied at least partially in a dedusting and cleaning downstream use of the heat energy of the gas.

For example, blast furnace gas has a specific heat capacity of approx. 1.4 kJ / Nm3K - a heating of around 500,000 Nm3 / h requires around 200 kW / K Fleizleistung. To get from 60 ° C to 100¾ requires 200 * 40 = approx. 8 MW Fleizleistung, which must be applied, for example, by burners or heat exchangers. About a TRT gas relaxation turbine can be recovered about 10 MW.

Likewise, the present invention solves the problem of making accessible to the solids contained in the gas and other entrained substances in the gas, since the materials obtained in the pre-separation, dedusting and purification are obtained separately from each other.

The present invention will be described by way of example and schematically with reference to the attached figures and explained with reference to the following description.

Fig. 1 shows an apparatus for carrying out an embodiment of the inventive method.

FIG. 2 shows a modified version of the device according to FIG. 1.

In a supply line 1 of Figure 1, a gas stream from in a pig iron production unit, not shown, to which the supply line 1 is connected, led in the production of pig iron accumulating gas. In the supply line 1, a pre-separation device 2, in this case a cyclone, is present. The coarse solid particles deposited in the pre-separation with a grain size of 10 to 200 .mu.m can be removed from the cyclone, which is represented by an arrow emanating from the cyclone. The from the 8/12 Austrian Patent Office AT12170U1 2011-12-15

Cyclone removed material contains no additive. It contains ferrous dust - a valuable raw material which is particularly well suited due to the absence of additive to be introduced into the pig iron production unit, not shown. Because the material contains no additive, such an additive does not introduce any additive into the pig iron production unit. At the junction 3, the supply line 1 branches into a bypass line 4, which opens into a chimney 5, and into a primary gas line 6. The primary gas line 6 is connected to three connecting lines 7,8,9, which in turn in each case a dedusting device 10, 11th , 12 open. Through the primary gas line 6 and the connecting lines 7, 8, 9 of the already pre-separated gas stream is passed into the dedusting device 10, 11, 12. Between the preseparating device 2 and the branch 3, a device for adjusting the temperature of the gas flow discharged from the preseparating device is present in the primary gas line 6, in this case an arrangement of parallel plate heat exchangers 21a and 21b. If the outlet temperature of the one plate heat exchanger exceeds the maximum permissible gas temperature for the dedusting devices, the system switches over to the other, with the hot plate heat exchanger, for example, being recooled with ambient air in the meantime.

Between the preseparation device 2 and the dedusting devices 10, 11, 12, a further device for adjusting the temperature of the gas stream discharged from the preseparation device is present in the primary gas line 6, in this case an evaporative cooler 13, in which the gas flow with water and / or or additive suspension is treated. Furthermore, in the primary gas line 6, a device for adding particulate dry solid additive 14, in this case a device for pneumatic pressure injection, is present. This is located behind the plate cooler and in front of the evaporative cooler. The addition of additive is symbolized by an arrow. The dedusting devices 10, 11, 12 comprise devices for removing separated solid particles 15, 16, 17. Via the solid particle line 18 emanating therefrom, which opens into the primary gas line 6 upstream of the first connecting line 7, viewed in the flow direction of the gas flow or from the branch 3, In the dedusting deposited solid particles are added to the gas stream. The addition takes place via a device not shown here for pneumatic pressure injection.

The in dedusting downstream processes such as blast furnaces, coke oven plants, raw material drying plants such as coal drying plant or fine coal drying plant, steam power plants, gas and steam power plants, used in pig iron production units in the production of pig iron or iron production units in iron production, dedusted and purified gas become. It can also be used in the internal process of pig iron or iron production as a reducing gas after gas spreading, for example by CO 2 reforming with natural gas, or CO 2 removal, and be returned to the process of pig iron or iron production. In the embodiment of the invention shown in the figure, the dedusted and purified gas is used in a downstream process. About the Exhaust line 19, which opens into all dedusting, the dedusting exhaust gas, which is under a pressure between 2-6 x 105 Pa, ie 2 to 6 bar, passed to a gas expansion turbine (TRT) 20. In this the pressure energy of the exhaust gas is used to generate electricity. By the bypass line 5, the gas flow is passed only in the event of malfunction of Entustaubungsvorrichtungen.

FIG. 2 shows a device according to FIG. 1 with the following differences from FIG. 1. An evaporative cooler is not present. A device for removing separated solid particles from the pre-separation device 22 is shown. On the presentation of their mouth in a device for adding material into the pig iron production unit, from which the gas stream comes, was omitted for reasons of clarity. As viewed in the flow direction of the gas flow in front of the plate heat exchanger 21a, 21b, a burner 23 in the supply line 1 as part of a device for adjusting the temperature of the gas stream. The heat energy supplied by the burner is in the Gasentspan- 9/12

Claims (16)

Austrian Patent Office AT12170U1 2011-12-15 turbine, the downstream unit for the utilization of the heat energy of the cleaned and dedusted gas, partly used for power generation and energy use. This makes the process more economical. Feed line 1 Pre-separation device 2 Branching 3 Bypass line 4 Chimney 5 Primary gas line 6 Connecting line 7,8,9 Dedusting device 10,11,12 Device for adjusting the temperature of the gas stream 13 Device for adding additive 14 Device for removing separated solid particles 15,16,17 Solid particle line 18 Exhaust line 19 Gas expansion turbine (TRT) 20 Plate heat exchanger 21a and 21b Apparatus for removing separated solid particles from the preseparator 22 Burner 23 Claims 1. A process for dry dedusting and dry cleaning of dust and pollutant gas produced in pig ironmaking units in pig iron production or in ironmaking units in iron production Gas, in which a gas stream consisting of this gas is subjected to a dedusting after a pre-separation for the separation of coarse solid particles, in which dedusting in the already d Pre-separated gas stream containing solid particles are deposited from the gas stream, and the temperature of the gas stream is set before dedusting so that its temperature above 60 ° C, preferably above 100 ° C, and less than a damage to the dedusting performing devices causing Temperature is, characterized in that the gas stream before the dedusting additive is added, wherein the additive contains reagent and optionally adsorbent. 2. The method according to claim 1, characterized in that the additive is added to the gas stream by means of pneumatic pressure injection. 3. The method according to claim 1, characterized in that the additive is added to the gas stream by means of gravity dosing. 4. The method according to any one of the preceding claims, characterized in that a subset of the deposited during dedusting solid particles is added to the gas stream before the start of dedusting after completion of the pre-separation, preferably by means of pneumatic pressure injection. 10/12 Austrian Patent Office AT12170U1 2011-12-15 5. The method according to any one of the preceding claims, characterized in that at least a portion of the deposited in the pre-separation and / or dedusting solid particles is used as starting material for the production of pig iron or iron. 6. The method according to any one of the preceding claims, characterized in that the temperature of the gas stream is adjusted before dedusting by means of evaporative cooler. 7. The method according to any one of claims 1 to 5, characterized in that the temperature of the gas stream is adjusted before dedusting by means of plate heat exchanger. 8. System for carrying out a method according to one of the preceding claims, comprising a feed line (1) leading a gas stream from a pig iron production unit or an iron production unit, in which a preseparating device (2) is present, wherein the feed line (1) at a branch ( 3) in a bypass line (4) and in a primary gas line (6), comprising at least one dedusting device (10,11,12), wherein the primary gas line (6) via a connecting line (7,8,9) with the dedusting device (10 , 11, 12), and comprising a device for adjusting the temperature of the gas flow (13) upstream of the dedusting device (10, 11, 12) in the supply line (1) or the primary gas line (6), characterized in that a device for the addition of additive (14) in the primary gas line is present, wherein the device for adding additive (14) between the branch (3) and the Verzwei supply (3) from the first connecting line (7,8,9) is located. 9. Apparatus according to claim 8, characterized in that the device for adding additive (14) is a device for pneumatic pressure injection. 10. The device according to claim 8, characterized in that the device for adding additive (14) is a device for gravity dosing. 11. Device according to one of claims 8 to 10, characterized in that the dedusting device (10,11,12) comprises a device for removing deposited solid particles (15,16,17). 12. Device according to one of claims 8 to 10, characterized in that the pre-separation device (2) comprises a device for removing separated solid particles from the pre-separation device (22). 13. The apparatus according to claim 12, characterized in that from the device for removing separated solid particles (15,16,17) a solid particle line (18) emanates, in front of the of the branch (3) seen from the first connecting line (7) in the Primary gas line (6) opens. 14. Device according to one of claims 12 to 13, characterized in that from the device for removing separated solid particles (15,16,17) and / or from the device for removing separated solid particles from the pre-separation device (22) emanates a feed line, the in a device for adding material in the pig iron production unit or the iron-generating unit opens. 15. Device according to one of claims 8-14, characterized in that the device for adjusting the temperature of the gas stream (13) comprises an evaporative cooler and / or a plate heat exchanger (21 a, 21 b). 16. Device according to one of claims 8-14, characterized in that the device for adjusting the temperature of the gas stream (13) comprises a burner (23). For this 1 sheet drawings 11/12