DE212009000108U1 - Device for the dry cleaning of gas produced during pig iron / iron production - Google Patents

Abstract

A system for dry dedusting and dry cleaning of dust and polluted gas in pig ironmaking units or in ironmaking units in ironmaking, comprising a feed line (1) carrying a gas stream from a pig ironmaking unit or an ironmaking aggregate in which a pre-depositing device (2) is present, wherein the supply line (1) branches at a branch (3) into a bypass line (4) and into a primary gas line (6), comprising at least one dedusting device (10, 11, 12),
wherein the primary gas line (6) is connected to the dedusting device (10, 11, 12) via a connecting line (7, 8, 9),
and comprising a device for adjusting the temperature of the gas stream (13) in front of the dedusting device (10, 11, 12) in the supply line (1) or the primary gas line (6),
characterized in that
there is a device for adding additive (14) in the primary gas line, the device for adding additive (14) between the branch (3) and the device of the ...

Description

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 iron production gas or gas produced in coal gasification, and an apparatus for performing the method.

In the pig iron production in pig iron production units, for example blast furnace, COREX ^® plant, FINEX ^® plant, gasifier or the production of iron in iron production units, for example MIDREX ^® plants, HYL ^® plants, direct reduction (DR) plants based on COREX ^® / FINEX ^® export gas, large quantities of gases accumulate. 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.

Exemplary are the properties of the ^® in pig iron production in blast furnace, COREX Plant, or FINEX ^® plant resulting gases shown: blast furnace COREX ^® FINEX ^® Gas volume tr. [Nm ³ / h] 350,000 to 750,000 250000-400000 150000-350000 Gas temperature [° C] 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 CO ₂ 20-22 30-35 30-35 H ₂ 2-4 15-20 10-15 N ₂ 50-55 10-15 15-20 Dust loading [mg / Nm ³ ] In the accumulating gas 20000-25000 20000-25000 12000-37000 Pollutants in the resulting gas [mg / Nm ³ ] HCl 0.4 7 HF 0.1 <0.2 H ₂ S 70-100 30-100 BTX 150 150 PAH 40; max 140 40, max. 300

It is known to free the accumulating gas by means of wet process of dust and pollutants, but such methods raise the problem of having to process accumulating sludge and wash water.

In the Chinese patent application CN1818080 discloses a method of dry dedusting of a blast furnace-derived gas stream. 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 moisture contained in the gas stream, however, the problem may occur in such methods that the filter material of the separator glued and clogged, because in the gas entrained compounds, such as aqueous moisture or organic compounds, condense. That leads to a considerable Pressure loss on the filter material and loss of the filter effect and may make the replacement of the filter material with associated downtime necessary. 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.

To reduce the risk of sticking or clogging due to dew point falls below the gas temperature and associated condensation, are in CN1818080 Provided heat exchanger, which are traversed in the case too low temperature of the pre-separation leaving the gas stream and lift the gas temperature above the dew points. Measures for cleaning the exhaust gas of pollutants are in CN1818080 not taken.

The object of the present invention is to provide a process for dry dedusting for the exhaust gas produced during the production of pig iron, in which the risk of sticking and clogging of the filter for dedusting is reduced 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 or gas produced in coal gasification plants, in which an existing gas from this gas stream
is subjected to a dedusting after a pre-separation for the deposition of coarse solid particles, in which dedusting in the, optionally already pre-separated, the gas stream contained solid particles 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 temperature causing damage to the dedusting devices.

The inventive method is characterized
that additive is added to the gas stream prior to commencement of dedusting, the additive containing reagent and optionally adsorbent.

An iron making unit can be for example a blast furnace, a reduction shaft or gasifier according COREX ^® - or FINEX ^® process. In such aggregates, solid or liquid pig iron or steel precursor is produced.

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

In the optional pre-separation, the separation of coarse solid particles, which are carried in the gas stream, for example, in gravity chambers (dust bag) or cyclones occur. Coarse solid particles are solid particles with particle diameters> 10 microns 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 fine dust particles ≤ 2.5 microns and, if no pre-separation is carried out, even coarse solid particles are removed in the dedusting to dust concentrations ≤ 5 mg / Nm ³ from the gas stream.

If a preliminary separation is present, the temperature of the gas stream is adjusted before dedusting according to an embodiment of the method according to the invention after the preliminary 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 transient conditions of the process, such as collapse of a column of material in the reduction or melting shaft, starting and Abfahrsituation.

The dust removal takes place in filtering devices such as fabric filters made of glass or plastic fiber such as aramid or P84 ^{® ®} (polyimide) of circular construction, metal or ceramic filters.

In order to protect the devices in which the dedusting is carried out, 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, so adjusted in 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 of up to 1000 ° C can be used.

Gas generated in pig iron production in pig ironmaking plants or in ironmaking in ironmaking plants contains, among others, hydrogen sulphide, hydrogen chloride, hydrogen fluoride, heavy metals, organic pollutants such as dioxins / 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 additive is added to the gas stream before the start of dedusting 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 (OH) ₂ , Mg (OH) 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 H ₂ S, HCl or HF.

The additive may also contain organic and / or inorganic adsorbents, for example hearth furnace coke (HOK), 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 can also be a lime-carbon mixture with additives, as is known as under the trade name Sorbalit ^®.

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

The additive can also be injected as a suspension in water, for example, lime milk, into 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 pollutants contained in the gas can be removed 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 Abscheidend acting plant parts of the devices for dedusting, since the exhaust stream meets only then 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 additive is periodically removed together with the filter dust cake which forms in the course of dedusting on the filtering and separating components of the dedusting apparatus; 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 loading 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 preliminary separation is present, the gas stream is added according to an embodiment of the method according to the invention prior to 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 for use. 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 produced in pig ironmaking plants or in ironmaking factories in ironmaking, the material obtained in the pre-separation contains iron-containing dust - a valuable raw material which, for example, can be traced back to pig ironmaking or ironmaking. 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 pig iron or ironmaking units, during which the risk of clogging or sticking the filtering and separating acting equipment parts of the devices for dedusting due to the risk of Auskondensierens particular is large, dedusting can be carried out trouble-free compared to the prior art. 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.

In one embodiment, the additive consists of one or both of the reagent and adsorbent components, because additional ingredients of the additive that do not act as a reagent or adsorbent reduce the effect of the additive that can be achieved per unit mass of additive.

Admitted particulate dry additive has a particle size of 0.1 to 200 microns 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 larger its specific surface. 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 with a particle size below 0.1 microns economically no longer makes sense.

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 × 10 ⁵ Pa and 6 × 10 ⁵ 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 solid particles deposited during dedusting on filtering and separating devices for dedusting are removed periodically from these devices. Among the separated solid particles is also additive, which can still react with pollutants contained in the exhaust gas, 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.

Among the secluded from the filternd and abscheidend acting devices for dedusting solid particles are also carbon sources such as coal dust, open hearth HOK, Sorbalit ^®, and erzhaltiger dust and iron-containing dust.

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 is adjusted 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 designed, 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 load and pollutant load, with gas from pig iron and iron production aggregates. 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.

For carrying out the method according to the invention, a device is provided with a feed line leading a gas stream from a pig iron production unit or an iron production unit or a coal gasification plant, in which a preseparating device is present, wherein the supply line branches at a branch into a bypass line and into a primary gas line,
with at least one dedusting device,
wherein the primary gas line is connected to the dedusting device via a connecting line,
and wherein before the dedusting device in the supply line or the primary gas line, a device for adjusting 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, the exhaust gas to be cleaned and dusted, such as a blast furnace, a reduction shaft or gasifier according COREX ^® can - or FINEX ^® process be.

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

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

The pre-separation device includes, 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 <10 microns can be effectively separated 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 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, the device for removing separated solid particles is preceded by a solid particle line, which, viewed in the flow direction of the gas stream or from the branching in the bypass line and the primary gas 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 emits a metering line which opens into a device for adding material to the pig ironmaking unit or the ironmaking unit.

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 achieves the object of simplifying utilization of the energy contained in the gas, for example for generating electricity in a turbine connected downstream of the dedusting and cleaning process, for example an expansion turbine, or the constituents of the gas, for example in chemical processes. 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 for adjusting the temperature of the gas stream heating - for example by means of a burner - is necessary, 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 about 1.4 kJ / Nm ³ K - a heating of about 500,000 Nm ³ / h requires about 200 kW / K heating power. In order to come from the 60 ° C to 100 ° C 200 · 40 = about 8 MW heating power required, 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 the solids contained in the gas and other substances entrained in the gas accessible for use, as 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.

1 shows an apparatus for carrying out an embodiment of the method according to the invention.

2 shows a modified version of the device according to 1 ,

In a supply line 1 of the 1 is a gas stream in a pig iron, not shown, with which the supply line 1 connected, resulted in the production of pig iron accumulating gas. In the supply line 1 is a pre-deposition device 2 , in this case a cyclone, available. The deposited in the pre-deposition coarse solid particles having a particle size of 10 to 200 microns can be removed from the cyclone, which is represented by an outgoing from the cyclone arrow. The material removed from the cyclone 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 branches the supply line 1 in a bypass line 4 in a fireplace 5 opens, and in a primary gas line 6 , The primary gas line 6 is with three connecting lines 7 . 8th . 9 connected, in turn, in each case a dedusting device 10 . 11 . 12 lead. Through the primary gas line 6 and the connection lines 7 . 8th . 9 the already pre-separated gas stream is in the dedusting 10 . 11 . 12 directed. Between the pre-separation device 2 and the branch 3 is in the primary gas line 6 a device for adjusting the temperature of the gas stream discharged from the preseparating device is present, 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 pre-separation device 2 and the dedusting devices 10 . 11 . 12 is in the primary gas line 6 a further device for adjusting the temperature of the gas stream discharged from the preseparating device is present, in this case an evaporative cooler 13 in which the gas stream is treated with water and / or additive suspension. 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, available. 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 include devices for removing separated solid particles 15 . 16 . 17 , About the outgoing of these solid particles line 18 , which in front of the flow direction of the gas flow or from the branch 3 seen from first connection line 7 in the primary gas line 6 opens, deposited in the dedusting 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, for example, wood stoves, coke oven plants, raw material drying facilities 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 can be used thermally. 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 pipe 19 , which discharges into all dedusting devices, the dedusted exhaust gas, which is under a pressure between 2-6 × 10 ⁵ Pa, ie 2 to 6 bar, to a gas relaxation turbine (TRT) 20 directed. In this the pressure energy of the exhaust gas is used to generate electricity. Through the bypass line 5 the gas flow is only conducted in the event of malfunction of dedusting devices.

2 shows a device after 1 with the following differences 1 , An evaporative cooler is not available. A device for removing separated solid particles from the pre-separator 22 is drawn. On the representation of its mouth in a device for Addition of material to the pig iron production unit from which the gas stream originates has been omitted for reasons of clarity. In the flow direction of the gas stream seen in front of the plate heat exchanger 21a . 21b is 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 used in the gas relaxation turbine, the downstream unit to use the heat energy of the purified and dedusted gas, in electricity generation and energy use in part. This makes the process more economical.

LIST OF REFERENCE NUMBERS

1

supply line

2

Pre-separation device

3

branch

4

bypass line

5

fireplace

6

Primary gas line

7, 8, 9

connecting line

10, 11, 12

dedusting

13

Device for adjusting the temperature of the gas stream

14

Device for adding additive

15, 16, 17

Device for removing separated solid particles

18

Solid particle line

19

Exhaustleitung

20

Gas expansion turbine (TRT)

21a and 21b

Plate heat exchanger

22

Device for removing separated solid particles from the pre-separation device

23

burner

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• CN 1818080 [0005, 0006, 0006]

Claims (9)

A system for dry dedusting and dry cleaning of dust and polluted gas produced in pig ironmaking units in pig ironmaking or in ironmaking aggregates in ironmaking, comprising a feed line leading a gas stream from a pig ironmaking aggregate or an ironmaking machine ( 1 ) in which a pre-deposition device ( 2 ) is present, wherein the supply line ( 1 ) at a branch ( 3 ) in a bypass line ( 4 ) and into a primary gas line ( 6 Branched, comprising at least one dedusting device ( 10 . 11 . 12 ), the primary gas line ( 6 ) via a connecting line ( 7 . 8th . 9 ) with the dedusting device ( 10 . 11 . 12 ), and comprising a device for adjusting the temperature of the gas stream ( 13 ) in front of the dedusting device ( 10 . 11 . 12 ) in the supply line ( 1 ) or the primary gas line ( 6 ), characterized in that a device for adding additive ( 14 ) is present in the primary gas line, wherein the device for adding additive ( 14 ) between the branch ( 3 ) and that of the branch ( 3 ) seen from first connection line ( 7 . 8th . 9 ) is located. System according to claim 1, characterized in that the device for adding additive ( 14 ) is a device for pneumatic pressure injection. System according to claim 1, characterized in that the device for adding additive ( 14 ) is a device for gravity dosing. System according to one of claims 1 to 3, characterized in that the dedusting device ( 10 . 11 . 12 ) a device for removing separated solid particles ( 15 . 16 . 17 ). System according to one of claims 1 to 3, characterized in that the pre-separation device ( 2 ) an apparatus for removing separated solid particles from the pre-separation device ( 22 ). System according to claim 5, characterized in that the device for removing separated solid particles ( 15 . 16 . 17 ) a solid particle line ( 18 ), before the branching ( 3 ) seen from first connection line ( 7 ) into the primary gas line ( 6 ) opens. System according to one of claims 5 to 6, characterized in that of the device for the removal of deposited solid particles ( 15 . 16 . 17 ) and / or from the device for removing separated solid particles from the pre-separation device ( 22 ) emanates a metering line, which opens into a device for the addition of material in the pig iron production unit or the iron-generating unit. System according to one of claims 1-7, characterized in that the device for adjusting the temperature of the gas stream ( 13 ) an evaporative cooler and / or a plate heat exchanger ( 21a . 21b ). System according to one of claims 1-7, characterized in that the device for adjusting the temperature of the gas stream ( 13 ) a burner ( 23 ).

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