BRMU8903155U2 - process and apparatus for the dry removal of dust from and for cleaning gas produced during iron production or coal gasification - Google Patents

Abstract

PROCESS AND APPARATUS FOR DRIED DRYING FROM AND FOR GAS CLEANING DURING IRON OR COAL GASIFICATION. The present model relates to a method for dry dust removal and dry cleaning of dust-laden gas and pollutants, such as in the incident gas in the pig iron production systems, or in the incident in the production systems. of iron in the production of iron or gas produced in coal gasification systems, and to an apparatus for performing the method. In the process, an additive comprising reactant and alternatively absorbent material is added to the gas stream prior to the commencement of dust removal after a preliminary separation step and after the gas stream temperature is set to a temperature greater than 60 ° C. and lower than the temperature that would cause damage to the dust removal device. This additive cleans the gas stream and is removed from the gas stream along with the solid particles that were present in the gas stream prior to the addition of the dust removal additive.

Description

Utility Model Patent Descriptive Report for "PROCESS AND APPARATUS FOR DUST DRY REMOVAL FROM AND FOR GAS CLEANING DURING IRON PRODUCTION OR COAL GASIFICATION".

The present model relates to a process for the dry removal of dust from and cleaning of dust-laden gas and pollutants such as gas produced in pig iron production units during pig iron production. or gas produced at the iron production units during the production of the iron or gas produced at the coal gasification plants, and also to an apparatus for performing the process.

During the production of pig iron in pig iron production units, for example, a blast furnace, a COREX® plant, a FINEX® plant and a carbonator, or iron production in iron production units, for example, MIDREX® plants, HYL® plants and COREX® / FINEX® export gas-based direct reduction (DR) plants · large quantities of gases are produced. These gases carry a large amount of dust with high proportions of fine solid particles and also a large number of gaseous pollutants. Firstly, during non-solid state operation, that is, particular operating situations such as starting or stopping the pig iron or iron production process or spontaneous process anomalies such as spontaneous sliding of the material column in the units, Particularly high amounts of dust and pollutants in gases and also in gas temperature peaks may increase. Before the gases are discharged into the environment or before they are used in subsequent processes, the dust must be separated and the gas must be cleaned of pollutants.

As an example, the properties of the gases produced during the production of pig iron in a blast furnace, a COREX® plant or a FINEX® plant are shown.

COREX® FINEX® Blast Furnace Gas Amount [Nm%] 350000-750000 250 000-400 000 150 000-350 000 COREX® FINEX® Blast Furnace Temperature 100-200; max 800 300; max 600 400-450; max 600 King gas pressure 250; max 350 320 220-320; max 600 [kPal Gas Composition [vol%] Co 20-25 35-40 20-25; max 75 Co2 20-22 30-35 30-35 H2 2-4 15-20 10-15 N2 50-55 10-15 15-20 Charge of Dust 20 000-25 000 20 000-25 000 12 000-37 000 [ mg / Nm3] in the produced gas Pollutants in the produced gas [mg / Nm3] HCl 0.4 7 HF 0.1 <0.2 H2S 70-100 30-100 BTX 150 150 PAH 40; max 140 40; max 300

It is known to remove dust and pollutants from gas produced by

wet processes, but such processes give rise to the problem of having to treat the sludge and wash water that is produced.

Chinese Patent Application CN1818080 describes a process for the dry removal of dust from a gas stream emanating from the blast furnace. In this process, the gas stream is subjected to dry dust removal through filter separators after preliminary separation in a separation chamber. During operating situations outside solid-state operation of the blast furnace, for example during startup or shutdown, or in the case of pollution gas temperatures below the dew point of moisture present in the gas stream, however, such processes may give rise to the problem that the separator filter material adheres and causes clogging because compounds carried along with the gas, for example aqueous moisture or organic compounds, condense. This results in a considerable pressure loss of the filter material as well as a loss of filter action, and may make it necessary to change the filter material, which is associated with idle operating time. If the appliance on which dust removal is performed is unavailable due to such problems, the dust-laden gas must be discharged into the environment through a bypass without further cleaning. Such derivation situations cause damage to the environment and are not permissible in many industrialized countries.

To reduce the risk of sticking or clogging due to low dew point value by gas temperature and associated condensations, the CN1818080 provides heat exchangers which, in the event that the temperature of the gas stream leaving the preliminary separation it is very low, they are crossed and the gas temperature rises above dew points. No measures to clean gas from pollutants are taken on CN1818080.

The present model is based on the objective of providing a dry dust removal process for the exhaust gas produced during the production of pig iron, in the case of which the risk of clogging and filter clogging occurs. dust removal is reduced and at the same time the exhaust gas is cleaned of pollutants. Similarly, an apparatus must be provided to perform the process.

This objective is achieved by a process for the dry removal of dust from and the dry cleaning of gas laden with dust and pollutants such as gas produced in pig iron production units during the production of pig iron or gas produced in pig iron. Iron production units during the production of iron or gas produced in coal gasification plants, in the processes of which a gas stream consisting of the said gas is subjected to dust removal after a preliminary separation to separate Crude solid particles, during which dust removal the solid particles present in the gas stream which, if appropriate, have already undergone preliminary separation, are separated from the gas stream, and the temperature of the gas stream prior to removal of The dust is adjusted such that the temperature of said gas stream is greater than 60 ° C, preferably greater than 100 ° C, and lower than the temperature it protects. damage to the appliance that performs dust removal.

The process according to the model is characterized by the fact that a reagent containing additive and, if appropriate, an absorbent is added to the gas stream prior to the commencement of dust removal.

As an example, a pig iron production plant may be a blast furnace, a reduction shaft or a gasifier smelter according to the COREX® or FINEX® process. Solid or cast iron or a primary steel product is produced in such units.

As an example, an iron production unit could be a MIDREX® plant, a HYL® plant or a COREX® / FINEX® export gas-based direct reduction plant. Sponge iron or agglomerated iron is produced in such units.

During the preliminary separation, which is optionally present, crude solid particles carried along with the gas stream may be separated, for example, in gravitational chambers (dust collector) or cyclones. Here, gross solid particles should be understood to mean solid particles having diameters> 10 μιη.

Since the preliminary separation effectively separates only gross solid particles up to the order of magnitude of the lower limit specified above, solid particles that are smaller than this lower limit are still present in the gas stream after said preliminary separation. . Such solid particles including fine 2.5 µm fine dust particles and, if no preliminary separation is performed, also crude solid particles are removed from the gas stream during removal to dust concentrations <5 mg / Nm3.

If preliminary separation is performed, the temperature of the gas stream prior to dust removal is adjusted according to a process configuration according to the model after preliminary separation.

The gas temperature during pig iron production or iron production fluctuates, for example, depending on the process used or depending on the occurrence of non-solid state states of the process, for example, the collapse of the material column in the reduction or a founding axis or a starting or stopping situation.

Dust removal occurs on filtration apparatus such as cloth filters made of fiberglass or synthetic fibers such as Aramid® or P84® (polyimide fibers) having a round construction type, metal filters or ceramic filters. To protect appliances in which dust removal is performed against condensation problems, which causes the separate filter cake to stick during dust removal, and against gas stream temperature spikes, gas prior to dust removal after optional preliminary separation is adjusted so that the temperature of the gas stream subjected to dust removal is above 60 ° C, preferably above 100 ° C, and below a temperature that would cause damage to the dust removal device. In the case of cloth filters, the temperature should be below 260 ° C, preferably below 200 ° C, as cloth filters undergo decomposition by the induced heat of the cloth filter at gas temperatures above 260 ° C. . In the case of ceramic or metal filters, gas temperatures of up to 100 ° C may be employed.

Gas produced during pig iron production in pig iron production units or gas produced during iron production in iron production units contains, inter alia, hydrogen sulfide, hydrogen chloride, hydrogen fluoride, heavy metals. , organic pollutants such as dioxins / furans, polycyclic aromatics, and other hydrocarbon compounds. These environmentally harmful exhaust gas components must be removed before the exhaust gas is discharged into the environment provided it is economically reasonable.

According to the model, a particulate additive, a dry additive or a suspension additive in water is added to the gas stream prior to the commencement of dust removal. The additive contains a reagent and, if appropriate, an absorbent.

The reagent is selected so that it reacts with the pollutants in the pig iron production plant exhaust gas to form particulate products that can be removed from the gas stream by dust removal. The reagent used is, for example, CaCO3, Ca (OH) 2, Mg (OH) 2 or sodium bicarbonate, or mixtures of two or more of these substances. The main task of the reagent is to separate acid polluting components such as H2S, HCl or HF.

The additive may also contain organic and / or inorganic absorbents, for example activated carbon / coke hearth coke (HOK) or finely ground zeolites. Pollutants present in the exhaust gas, for example heavy metals or organic pollutants, may be removed from the gas stream by absorption by absorbent, where the pollutant-laden absorbent product produced by absorption is particulate and may therefore , also be removed from the gas stream during dust removal.

The additive may also be a carbon-cation mixture with additions, as known, for example, under the tradename Sorbalit®.

Particulate additive or particulate reaction products or additives charged as particulate absorbent material are removed from the gas stream again during dust removal.

The additive may also be injected into the gas stream as a suspension in water, for example lime milk. A suitably high gas temperature> 150 ° C is required for addition in the form of a suspension. If the additive is added to the gas stream in the form of a suspension, the liquid evaporates into the hot gas stream, and therefore the additive can be removed by dusting off as a particulate, dry additive material.

Since gas cooling also occurs if the additive is added in the form of a suspension, this type of addition can be coupled with process steps to adjust the gas temperature.

The addition of additive according to the model has the advantage that

Pollutants in the gas can be removed at the same time from dust removal from the gas stream.

Another advantage is that both reagents and absorbers can retain moisture present in the gas stream and therefore the moisture condensation risk of the gas stream is reduced. .

It is further advantageous that the additive, or particulate products produced in reaction with the reagent or absorption in the absorber, is deposited in the filtration and separation of the dust removal apparatus and the said apparatus is therefore coated. On the other hand, such a separate filter cake additive coating contributes to dust removal since the gas stream has to pass through it. On the other hand, it protects parts of the filtration and separation apparatus from the dust removal apparatus, since the exhaust gas stream only collides with the latter once it has passed through the coating. The risk of clogging or sticking of the parts of the filtration apparatus and separation of the dust removal apparatus is therefore reduced as the gaseous stream organic contents or moisture and / or fine adhesive solid particles may already partially be separated into the filter cake. The protection of the appliance parts thus achieved results in

an extended service life. The additive coating is periodically removed along with the filter dust cake that forms during the course of dust removal on the parts of the filter apparatus and separation of the dust removal apparatus; This removal is cheaper and less complicated than the removal of solid particles that have penetrated parts of the filtration apparatus and separation of the dust removal apparatus.

According to one embodiment, the addition of additives is performed depending on the loading of the gas with pollutants. In this context, the pollutant content is measured and an appropriate addition of additives is triggered or increased if the operator preset minimum values for raw or clean gas are exceeded. In this context, crude gas should be understood as meaning gas before cleaning, and clean gas should be understood as meaning gas after dry cleaning. It is preferable for this to consider individual types of pollutants. According to a preferred embodiment, the reagent type in the additive is selected based on the considered pollutant. It is therefore possible to add the reagent that is optimally suitable for the pollutant in question. As a result, reagent consumption costs can be minimized and the resulting amounts of solid particles separated during dust removal can be reduced. This simplifies proper use.

If preliminary separation is performed, the additive is added to the gas stream according to a process configuration according to the model prior to the commencement of dust removal after preliminary separation. Removal of additives from the gas stream is therefore avoided even before dust removal. Otherwise, the duration of the additive permanence in the gas stream would be reduced compared to separation during dust removal, and consequently the additive cleanability would be exploited to a lesser extent. Since the additive is only added to the gas stream after preliminary separation, the material obtained during preliminary separation contains no additives. Due to the absence of additive, said material is particularly well suited for use. Since the material does not contain any additives, it is not necessary to take into account any additives present in the case of such use. As an example, the use may be at least partial recirculation of the material in the process in which the gas to be cleaned is produced. However, the material can also be used in other processes. If the gas to be cleaned is produced in pig iron production units during pig iron production or in iron production units during iron production, the material obtained during preliminary separation contains iron-containing dust - a material valuable cousin which, as an example, can be recirculated back to pig iron production or iron production. If the gas to be cleaned is produced in coal gasification plants, the material obtained during preliminary separation contains coal-containing dust - a valuable raw material that can be recirculated as an example in the coal gasification plant.

Relimental separation has the advantage that plant parts through which gas flows after preliminary separation are subjected to less charge by contact with solid particles.

The process according to the model therefore has an effect that dust removal can be performed with less interruption compared to the prior art even in operating states such as starting and stopping or in case of operational disturbances of the units. pig iron or iron production, during which the risk of clogging or sticking of the parts of the filtration plant and separation of the dust removal apparatus is particularly high due to the risk of condensation. Since, therefore, dust removal and pollutant cleaning can be performed even in such operating states, it is virtually no longer necessary to discharge the gas laden with dust and pollutants through a bypass into the environment.

According to one embodiment, the additive consists of one or both of reactant and absorbent components; This is because additional additive constituents that do not act as a reagent or absorbent reduce the achievable effect of the additive per unit mass of the additive.

Particulate dry additives, which are added, have a grain size of 0.1 to 200 pm. This grain size ensures that the additive is evenly distributed in the gas stream. If a significant proportion of grain sizes exceed this range, homogeneous distribution in the gas stream would be difficult, and this would lead to low separation rates during dust removal. The smaller the grain size of the additive, the larger its specific surface area. As the specific surface area increases, it becomes possible for pollutant and reaction reaction and also moisture binding procedures to proceed more effectively. However, the price of the additive increases as grain size becomes smaller, and therefore the use of additive having a grain size of less than 0.1 pm is no longer economically reasonable.

Exhaust gas from pig iron production units is generally at high pressure. The absolute exhaust gas pressure of the pig iron production units is between 2 χ 105 Pa and 6 χ 105 Pa, ie between 2 and 5 bar. This pressure has to be overcome during the addition of the additive to the gas stream. This preferably occurs by means of pneumatic pressure injection of the additive.

As an alternative, dry additives may also be introduced by gravitational dosing, in which case it must be ensured that the excess pressure is sealed from the outside, for example by means of star feeders or double swivel closures.

During the addition of the additive to the gas stream, it is necessary to ensure that the additive is evenly distributed. This can be accomplished, for example, using a so-called static mixer (in the case of gravitational dosing) or an appropriate number of injection lances (in the case of pressure injection).

Suspensions are preferably introduced by two-fluid nozzles, the liquid suspension being atomized by gas or vapor.

Solid particles that are separated during dust removal in the filtration and separation of dust removal apparatus are periodically removed from said apparatus. Separate solid particles also include additives which may further react with the exhaust gas pollutants, absorbent pollutants or moisture bonding.

Therefore, according to a process configuration according to the model, a partial amount of the solid particles separated during dust removal as a filter cake is added to the gas stream prior to the commencement of dust removal as the Optional preliminary separation has been completed. This recirculation of additives in the gas stream increases the effect achievable per unit amount of additive; This is because the reaction, absorption and moisture binding potentials that are still unused after the first addition of an additive amount can be used after the renewed addition to the gas stream. Compared to a process without recirculation, it is therefore possible to achieve the same effect with less fresh additive, and this automatically reduces the amount of filter cake to be removed. Due to the exhaust gas pressure, the addition preferably

It occurs through pneumatic pressure injection, but may also occur, for example, through gravitational dosing. The solid particles separated by filtration and separation dust removal apparatus also include carbon carriers such as coal dust, sill kiln (HOK), Sorbalit® and ore-containing dust and iron-containing dust.

To use this material in the production of pig iron or in the production of iron or coal gasification, according to an advantageous process configuration according to the model, at least a partial amount of the solid particles separated during preliminary separation and / or dust removal as a filter cake is used as a starting material for the production of iron or for the production of iron or for gas produced in coal gasification plants. This improves their economic viability and utilizes the separated solid particles in a manner which is simpler than would otherwise be the case for disposal. As an example, however, the material can also be used after possible pre-treatment steps in a steelmaking process (converter, electric furnace) or in a sintering process.

According to a process configuration according to the model, the temperature of the gas stream subjected to dust removal is adjusted by means of an evaporation chiller. This has the advantage that the temperature can be stably regulated to a desired temperature even for long periods of time.

According to another process configuration according to the model, the temperature is adjusted by means of a plate-type heat exchanger. This has the advantage that no additional water injections have to be provided and the average gas temperature or sensitive gas heat is higher. As an example, this increases energy efficiency for subsequent use in a gas expansion turbine compared to temperature setting by means of an evaporation cooler.

In this case, there are usually two variant modalities. Or the gas is guided through a heat accumulator only when the maximum operating temperature of the dust removal apparatus (eg 260 ° C) is exceeded, and is guided by said heat accumulator again when the temperature is reduced, or two plate-type heat exchangers are connected in parallel. If the discharge temperature of one heat accumulator exceeds the maximum operating temperature, a switch to the other heat accumulator is made, the hot accumulator being cooled in the meantime in the meantime, for example. Coal gasification plants, which may be designated, for example, as a fixed bed gasifier or a strained flow gasifier, produce a gas comparable in terms of their properties, in particular with respect to dust loading and gas loading. pollutants from the pig iron and iron production units. Gas from coal gasification plants is used, inter alia, as a reducing gas during the production of pig iron or iron.

According to a process configuration according to the model, the gas to be subjected to dry dust removal and dry cleaning comes from a coal gasification plant.

The process according to the model is carried out using an apparatus comprising a feed line which conducts a gas stream from a pig iron production unit or an iron production unit or a coal gasification plant and in which there is a preliminary separation device, wherein the feed line branches at a branch point on a branch line and a primary gas line, comprising at least one dust removal apparatus, where the primary gas is connected to the dust removal apparatus via a connection line, and where an apparatus for adjusting the

gas is present after the dust remover on the power line or primary gas line.

Said apparatus is characterized by the fact that

There is an additive adding apparatus in the primary gas line, where the additive adding apparatus is located between the branch point and the first connecting line as seen from the branch point.

As an example, the pig iron production plant whose exhaust gas must be cleaned and dust-free may be a blast furnace, a reduction shaft or a gasifier melter in accordance with the COREX® or FINEX® process. As an example, an iron production unit could be a MIDREX® plant, a HYL® plant or a COREX® / FINEX® export gas-based direct reduction plant.

The supply line that runs a gas stream from a pig iron production unit or an iron production unit is connected to the pig iron production unit or the iron production unit.

The preliminary separation device comprises, for example, a gravitational settling chamber, a cyclone, a Hurriclon® or an electrostatic filter. Such apparatus may be used to effectively separate crude solid particles from the gas stream.

The dust removal apparatus comprises, for example, a round filter with filter pockets of textile, ceramic or metallic fabric. Such apparatuses can be used to effectively separate extremely fine solid particles <10 pm from the gas stream.

Preliminary separation devices and dust removal devices of this type are capable of operating at the gas pressure from which dust must be removed.

According to one embodiment of the apparatus depending on the model, the apparatus for adjusting the gas stream temperature is located between the preliminary separation device and the dust removal apparatus.

According to a plant configuration according to the model, the apparatus for adding dry particulate additives is an apparatus for pneumatic pressure injection.

According to another model embodiment of the plant, the apparatus for adding additives is a gravity metering apparatus.

According to one embodiment of the apparatus according to the model, the dust removal apparatus comprises an apparatus for removing separated solid particles.

According to one embodiment of the apparatus according to the model, the preliminary separation device comprises an apparatus for removing solid particles separated from the preliminary separation device. According to another embodiment of the apparatus depending on the model, a solid particle line emanates from the apparatus to remove separated solid particles and pours into the primary gas line after the first connection line as seen in the direction of current flow. as seen from the branch point on the branch line and the primary gas line. The release point is advantageously provided with a pneumatic pressure injection apparatus whereby solid particles can be introduced into the primary gas line as opposed to the gas stream pressure.

According to another embodiment of the apparatus depending on the model, an addition line emanates from the solid particulate removal apparatus and / or the separated solid particulate removal apparatus from the preliminary separation device and pours into an apparatus for adding material. to the pig iron production unit or the iron production unit. According to another embodiment of the apparatus depending on the model, the apparatus for adjusting the temperature of the gas stream comprises an evaporation cooler.

According to another embodiment of the apparatus depending on the model, the apparatus for adjusting the gas stream temperature comprises a plate-type heat exchanger or other types of heat exchangers such as pipe bundles, forced current chillers and heat exchangers Ljüngstrom.

According to another embodiment of the apparatus depending on the model, the apparatus for adjusting the gas stream temperature comprises a torch. The torch makes it possible to rapidly increase the temperature of the gas stream above the lower limit of 60 ° C - and generally with simple and easily controllable apparatus.

The fuel supplied to the torch is a combustible gas or a mixture of combustible gas. It is preferable to use at least part of the dry-dust and dry-clean gas obtained in the process as the model fuel for the torch.

According to another embodiment, the supply line conducts a gas stream from a coal gasification plant connected thereto. The present model also achieves the goal of simplifying the use of energy present in the gas - for example to generate electricity in a turbine after the dust removal and cleaning process, for example an expansion turbine - or gas constituents - for example. in chemical processes. Such uses are simplified by cleaning and dusting depending on the model, as the plant parts employed for such uses are to a lesser extent exposed to attacks by solid and polluting particles, which may have, for example, an action. abrasive and corrosive.

If heating - for example by means of a blowtorch - is necessary to adjust the temperature of the gas stream, it is advantageous to recover the thermal energy supplied in the process at least partially in a use of the gas thermal energy after dust removal and drying. cleaning. As an example, the top gas has a specific thermal capacity of about 1.4 kJ / Nm3K - heating of about 500 000 Nm3 / h requires a heating power of about 200 kW / K. To heat from 60 ° C to 100 ° C, 200 * 40 = about 8 MW of heating power is required, and this has to be applied, for example, by a torch or heat exchanger. About 10 MW can be recovered using a TRT gas expansion turbine.

Similarly, the present model achieves the goal of making solids present in gas and other gas-transported substances available for use, from materials obtained during preliminary separation, dust removal and cleaning are obtained separately from each other.

The present model is illustrated by way of example and schematically on the basis of the attached figures and explained on the basis of the following description.

Figure 1 shows an apparatus for executing a process mode according to the model.

Figure 2 shows a modified version of the device shown.

in figure 1.

A feed line 1, shown in Figure 1, conducts a stream of gas produced in a pig iron production unit (not shown) to which the feed line 1 is connected during pig iron production. A preliminary separation device 2, in this case a cyclone, is present in the feed line 1. Crude solid particles separated during preliminary separation, having a grain size of 10 to 200 pm, can be removed from the cyclone, this being shown. by an arrow emanating from the cyclone. The material removed from the cyclone contains no additives. It contains dust containing iron - a valuable raw material - which, due to the absence of additives, is particularly well suited for introduction into the pig iron production facility (not shown). Since the material does not contain any additives, no additives are introduced into the pig iron production plant if such introduction occurs. Feed line 1 branches at branch point 3 into a branch line 4, which launches into a chimney 5, and into a primary gas line 6. Primary gas line 6 is connected to three connecting lines 7,8,9, which in turn are launched into a respective dust removal apparatus 10, 11, 12. The gas stream which has already been subjected to preliminary separation is conducted through the primary gas line 6 and connection lines 7, 8, 9 in the dust removal apparatus 10,11,12. An apparatus for adjusting the temperature of the gas stream conducted outside the preliminary separation device, in this case a plate type heat exchanger arrangement 21a and 21b connected in parallel, is present between the preliminary separation device 2 and branching point 3 on the primary gas line 6. If the discharge temperature of a plate type heat exchanger exceeds the maximum gas temperature allowable for apa dust removal, a switch is made to the other plate-type heat exchanger, the hot plate-type heat exchanger also being cooled in the meantime with ambient air, for example.

Another apparatus for adjusting the temperature of the conducted gas stream outside the preliminary separation device, in which case an evaporation cooler 13 in which the gas stream is treated with water and / or additive suspension, is present between the separation device. 2 and dust removal appliances 10,11,12 on the primary gas line 6.

Additionally1 an apparatus for adding dry particulate solid additive 14, in this case an apparatus for pneumatic pressure injection is present in the primary gas line 6. Said apparatus is arranged downstream of the plate-type chiller and before the evaporation chiller. The addition of additives is symbolized by an arrow. Dust removal apparatuses 10, 11, 12 comprise apparatus for removing separate solid particles 15,16,17. Separate solid particles during dust removal are added to the gas stream through the particle line. solid particles 18 emanating from said apparatuses and launching into the primary gas line 6 upstream of the first connection line 7, as seen in the direction of flow of the gas stream or branching point 3. Addition occurs using a device for pneumatic pressure injection (not shown here).

Gas that is produced in pig iron production units during pig iron production or in iron production units during iron production and is dusted and cleaned according to the model can be thermally used in processes. downstream of dust removal, eg blast furnaces, coke ovens, raw material drying plants, eg a coal drying plant or a coal fines drying plant, steam thermal plants, or gas or steam thermal plants. It can also be used in the internal process for the production of pig iron or iron as a gas reduction after gas treatment, for example by CO2 reforming with natural gas or CO2 removal, and be recirculated from Back in the process for the production of pig iron or iron, in the embodiment of the model shown in the figure, clean, dusty gas is used in a later process. The exhaust gas that has been subjected to dust removal at a pressure of 2-6 χ 10δ Pa, ie 2 to 6 bar, is driven to a gas expansion turbine (TRT) 20 through the line. 19, which throws in all dust removal appliances. In said gas expansion turbine, the exhaust gas pressure energy is used to generate electricity. The gas stream is passed through the bypass line 5 only in the event of operational interruptions to the dust removal equipment.

Figure 2 shows an appliance as shown in figure 1, with the following differences compared to figure 1, There is no evaporation chiller. An apparatus for removing separated solid particles from the preliminary separation device 22 is shown. For the sake of clarity, Figure 2 does not show the point at which said apparatus launches into an apparatus for adding material to the pig iron production unit from which the gas stream emanates. Upstream of the heat exchanger 21a, 21b, as seen in the direction of flow of the gas stream, there is a torch 23 in the supply line 1 as part of an apparatus for adjusting the gas stream temperature. The thermal energy supplied by the torch is used to some extent in the gas expansion turbine, the downstream unit to use the clean and dusty gas thermal energy for conversion to electricity and for energy use. This makes the process more economical. REFERENCE LIST 1 Feed line 2 Preliminary separation device

3 Branch Point

4 Bypass Line

Chimney

6 Primary Gas Line 7, 8, 9 Connection Line

10,11,12 Dust Removal Device

13 Apparatus for adjusting the temperature of the gas stream

14 Device for adding additive

15,16,17 Apparatus for removing separated solid particles 18 Solid particle line

19 Exhaust Line

Gas Expansion Turbine (TRT)

21a and 21b Plate Type Heat Exchanger

22 Apparatus for removing separated solid particles from the preliminary separation device

23 Blowtorch

Claims (16)

1. Process for the dry removal of dust from and for the dry cleaning of gas laden with dust and pollutants such as gas produced in pig iron production units during the production of pig iron or gas produced in iron production units in iron production, in which processes the gas stream consisting of solid gas is subjected to dust reduction after preliminary separation to separate crude solid particles, during which dust removal the solid particles present The gas stream that has already been subjected to preliminary separation is separated from the gas stream, and the temperature of the gas stream prior to dust removal is adjusted so that the temperature of said gas stream is greater than 60 °. C, preferably greater than 100 ° C, and lower than the temperature that would cause damage to dust removal apparatus, characterized in that an additive containing a If appropriate, an absorbent is added to the gas stream prior to the commencement of dust removal. Process according to Claim 1, characterized in that the additive is added to the gas stream by pneumatic pressure injection. Process according to Claim 1, characterized in that the additive is added to the gas stream by gravitational dosing. Process according to the preceding claims, characterized in that a partial amount of the solid particles separated during dust removal is added to the gas stream prior to the commencement of dust removal since the preliminary separation has been completed, preferably by pneumatic pressure injection. Process according to the preceding claims, characterized in that at least a partial amount of solid particles separated during preliminary separation and / or dust removal is used as a starting material for the production of pig iron or for the production of iron. Process according to the preceding claims, characterized in that the temperature of the gas stream is adjusted prior to dust removal by means of an evaporation cooler. Process according to Claims 1 to 5, characterized in that the temperature of the gas stream is adjusted prior to removal by means of a plate-type heat exchanger. Apparatus for carrying out the process as defined in the preceding claims, comprising a supply line (1) which conducts a gas stream from a pig iron production unit or an iron production unit and in which there is a preliminary separation device (2), wherein the feed line (1) branches at a branch point (3) into a branch line (4) and a primary gas line (6), comprising at least one dust removal apparatus (10, 11, 12), wherein the primary gas line (6) is connected to the dust removal apparatus (10, 11, 12) via a connection line ( 7, 8, 9), and wherein an apparatus for adjusting the gas stream temperature (13) is present before the dust removal apparatus (10, 11, 12) on the supply line (1) or primary gas (6), characterized by the fact that there is an apparatus for adding additives (14) to the primary gas line in which and the additive addition apparatus (14) is located at the branch point (3) and the first connecting line (7, 8, 9) as seen from the branch point (3). Apparatus according to claim 8, characterized in that the additive adding apparatus (14) is a pneumatic pressure injection apparatus. Apparatus according to claim 8, characterized in that the additive addition apparatus (14) is a gravitational metering apparatus. Apparatus according to claims 8 to 10, characterized in that the dust removal apparatus (10, 11, 12) comprises an apparatus for removing separate solid particles (15, 16, 17). . Apparatus according to claims 8 to 10, characterized in that the preliminary separating device (2) comprises an apparatus for removing the separated solid particles in the preliminary separating device (22). Apparatus according to claim 12, characterized in that a solid particle line (18) emanates from the apparatus for the removal of separate solid particles (15, 16, 17) and lances in the primary gas line ( 6) upstream of the first connection line (7) as seen from the branch point (3). Apparatus according to claims 12 and 13, characterized in that an addition line emanates from the separate solid particulate removal apparatus (15, 16, 17) and / or the particulate removal apparatus. solids separated from the preliminary separation device (22) and cast into an apparatus for adding material to the pig iron production unit or iron production unit. Apparatus according to Claims 8 to 14, characterized in that the apparatus for adjusting the temperature of the gas stream (13) comprises an evaporation cooler and / or a plate-type heat exchanger (21a). 21b). Apparatus according to Claims 8 to 14, characterized in that the apparatus for adjusting the temperature of the gas stream (13) comprises a torch (23).