KR20110006780U - PROCESS AND APPARATUS FOR THE DRY REMOVAL OF DUST FROM AND FOR THE CLEANING OF GAS PRODUCED DURING THE PRODUCTION OF IRON OR COAL GAkSIFICATION - Google Patents

Abstract

The present invention is a method for dry removal and dry cleaning of a gas containing contaminants and dusts as a gas produced in a coal gasification system, a gas accompanying an iron production system in pig iron production or an iron production system in iron production. And means for performing the method. In the process, before the start of dust removal after the preliminary separation step and after the temperature of the gas stream is adjusted to a temperature above 60 ° C. and below a temperature that causes damage to the equipment performing the dust removal, the reaction An additive comprising an agent and optionally an absorbent material is added into the gas stream. The 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 additive upon removal of the dust.

Description

FIELD OF THE INVENTION APPARATUS AND APPARATUS FOR THE DRY REMOVAL OF DUST FROM AND FOR THE CLEANING OF GAS PRODUCED DURING THE PRODUCTION OF IRON OR COAL GAkSIFICATION}

The invention contemplates the use of gas, including dust and contaminants, such as gas produced in the pig iron production unit during the production of pig iron, or gas produced in the iron production unit during the production of iron, or gas produced in the coal gasification plant. It relates to a process for dry cleaning and for dry removal of dust from gases, and an apparatus for carrying out such processes.

During pig iron production in pig iron production units such as blast furnaces, COREX® plants, FINEX® plants and melt gasifiers, or based on MIDREX® plants, HYL® plants and COREX® / FINEX® exhaust gases During iron production in iron production units such as direct reduction (DR) plants, a large amount of gas is produced. These gases travel at high rates along with large amounts of dust and fine gaseous contaminants containing fine solid particles. During unsteady operation, in other words during special operating situations such as the start or stop of pig iron or iron production processes, or during spontaneous process anomalies such as spontaneous slipping of the column of material, a high amount of dust in the unit, in particular in the gas. And contaminants occur, and also peaks in the gas temperature. Before the gas is released into the environment or before they are used in downstream processing, the dust must be separated and the gas must be cleaned from the contaminants.

In one example, the properties of the gas produced during the production of pig iron in a blast furnace COREX® plant or FINEX® plant are as follows.

It is known to remove dust and contaminants from the produced gas by using a wet treatment, but this treatment has a problem of treating the slurry and wash water produced. Chinese patent application CN1818080 discloses a process for drying and removing dust from a gas stream derived from a blast furnace. In this process, dry dust removal is carried out in the gas stream using a filtering separator after the dry preliminary separation in the separation chamber. During operating conditions outside the steady-state of the blast furnace, for example, during start-up or shut-off, or below the dew point of water or below the acid dew point of moisture present in the gas stream. In the case of a gas temperature, the above treatment can stick to the filter material of the separator, forming a blockage, since the composite carried in the gas is condensed, for example, with moisture or organic compounds. This can lead to significant pressure loss of the filter material and loss of filter operation, and can result in the necessary exchange of filter material, which is associated with operating downtime. If the apparatus on which dust removal is performed becomes unavailable due to this problem, the dust-containing gas must be bypassed and released into the environment without further cleaning. This bypass situation causes damage to the environment and is unacceptable in many industrialized countries. In order to reduce the risk of sticking or blockage due to undershooting of the gas temperature and associated dew point due to condensation associated with it, CN1818080 does not provide gas above the dew point if the temperature of the pre-separated gas stream is too low. It provides a heat exchanger that raises and moves the temperature. A method of cleaning off contaminants off-gas is not disclosed in CN1818080.

The present invention aims at the dry dust removal treatment of off-gases produced during the production of pig iron, in which case the risk of sedimentation and blockage in the filter for dust removal is reduced, while at the same time It is cleaned from contaminants. Similarly, an apparatus for performing this process will be provided.

The invention is illustrated by way of example and schematically based on the accompanying drawings, which are explained on the basis of the following description.
1 shows an apparatus for performing an embodiment of a process according to the present invention.
FIG. 2 shows a modified version of the device shown in FIG. 1.

The above object is the gas produced in the pig iron production unit during the production of pig iron, or the gas produced in the iron production unit during the production of iron, or the gas produced in the coal gasification plant-the gas in the coal gasification plant The gas stream constituted is treated-a process for dry cleaning of the gas, including dust and contaminants, and for dry removal of the dust from the gas, in which the dust after preliminary separation for the separation of coarse solid particles Removal is effected, and during this dust removal, solid particles present in the gas stream for which the preliminary separation has already been made are separated from the gas stream, and the temperature of the gas stream is at least 60 ° C, preferably at least 100 ° C. And the temperature that causes damage to the device performing the dust removal. By way of example only, the temperature of the gas stream may be set prior to the dust removal. The process is characterized in that additives comprising reactants and, if appropriate, adsorbents are added to the gas stream before the start of the dust removal. In one example, the pig iron production unit is a blast furnace, reduction shaft or melt gas furnace associated with COREX® or FINEX® treatment. Solid or dissolved pig iron or primary iron products are produced in these units.

In one example, the iron production unit may be a MIDREX® plant, a HYL® plant, or a direct reduction plant based on COREX® or FINEX® exhaust gas. Sponge iron or briquetted iron are produced in this unit.

During the optionally provided preliminary separation, the coarse solid particles carried together in the gas stream can be separated, for example in a gravitational chamber (dust bag) or cyclone. Here, coarse solid particles are to be understood as meaning solid particles having a particle diameter larger than 10 μm. Since the preliminary separation effectively separates only to the extent that the coarse solid particle size is below the lower limit specified above, solid particles falling short of this lower limit are still present in the gas stream after the aforementioned preliminary separation. Solid particles as above, including fine dust particles of 2.5 μm or less, and coarse solid particles are also removed from the gas stream up to a dust concentration of 5 mg / Nm ³ or less during dust removal if no preliminary separation is performed.

If preliminary separation is carried out, the temperature of the gas stream before dust removal is set according to one embodiment of the process according to the invention after the preliminary separation.

 The temperature of the gas varies during the production of pig iron or iron, for example depending on the process used, or the non-steady state of the process, such as the collapse of the material column in the reduction or dissolution shaft, or the start and stop conditions. Fluctuates depending on the occurrence of

Dust removal is made from glass fibers, synthetic fibers such as Aramid® or P84® (polyimide fibers) and takes place in filtering devices such as fabric filters, metal filters or ceramic filters with rounded structures.

Before and after optional preliminary dedusting to protect the device from which dedusting is carried out from condensation problems which cause segregation of the separated filter mass during dedusting and from temperature peaks in the gas stream. The temperature of the gas stream is set such that the temperature of the gas stream from which dust removal takes place is at least 60 ° C., preferably at least 100 ° C., and below the temperature at which damage is caused to the apparatus performing the dust removal. In the case of a fiber filter, the temperature should be below 260 ° C., preferably below 200 ° C., because the fiber filter undergoes thermal induced decomposition of the fiber filter at a gas temperature of 260 ° C. or higher. In the case of ceramic filters or metal filters, it is possible to use gas temperatures up to 1000 ° C.

The gas produced during the production of pig iron in the pig iron production unit or the gas produced during the production of iron in the iron production unit is inter alia, hydrogen sulfide, hydrogen chloride, hydrogen fluoride, heavy metals, organic contaminants, for example Dioxin / furan, polycyclic aromatics and other hydrocarbon compounds. These environmentally harmful off-gas components must be removed to an economically reasonable degree before the off-gas is released into the environment.

According to the present invention, additives in the form of particles, dried additives or additives in the form of suspensions in water can be added to the gas stream before the start of dust removal. Additives include reactants and, if appropriate, adsorbents. The reagent is selected to react with contaminants present in off-gases from the pig iron production plant to form particle products that can be removed from the gas stream by dust removal. The reactants used are, for example, CaCO ₃ , Ca (OH) ₂ , Mg (OH) ₂ or sodium hydrogen carbonate or a mixture of two or more of these substances. The main task of the reactants is to isolate acidic contaminant components such as H ₂ S, HCl or HF.

The additives may include organic and / or inorganic absorbents, such as hearth furnace coke (HOK), activated carbon / coke or fine abrasive zeolites. Contaminants, such as heavy metals or organic contaminants, present in the off-gas can be removed from the gas stream by absorption using an absorbent, wherein the pollutant-containing absorbent product produced by absorption is in particulate form, It can thus be removed from the gas stream during dust removal. The additive may also be a lime-carbon mixture with additives, for example known under the trade name Sorbalit®. Particulate additives or particulate reaction products or particulates with adsorbent inclusions of additive components can be removed from the gas stream again during dust removal.

The additive may also be injected in the gas stream in the form of a suspension in water, for example in the milk of lime. Suitably gas temperatures higher than 150 ° C. are required for additives in the form of suspensions. If the additive is added in the gas stream in the form of a suspension. The liquid evaporates in the hot gas stream, so the additive can be removed during dust removal as a dry additive in the form of particles. Since gas cooling can also occur if the additive is added in the form of a suspension, this type of additive can be associated with the process step of setting the gas temperature.

The addition of additives according to the present invention has the advantage that contaminants present in the gas can be removed simultaneously with the removal of dust from the gas stream. Another advantage is that both the reactant and the adsorbent bind water present in the gas, so that water condensation from the gas stream can be reduced. A further advantage is that the additives or particulate products produced during the reaction with the reactants or upon the adsorption action of the adsorbent are deposited on the filtering and separating dust removal apparatus. As a result, the device is coated. On the other hand, the coating of the additive comprising the separated filter cake contributes to the removal of dust since the gas stream has to pass through it. On the other hand, it protects the filtering and separation equipment part of the dust removal device because only the off-gas stream is affected when it passes through the coating. Since the organic gas content or moisture and / or microadsorbent solid particles of the gas stream can already be partially separated in the filter cake, the result can be reduced risk of sticking or obstruction of the filtering and separation plant parts of the dust removal device. have. The protection of the plant part achieved as a result leads to an increased service life.

The additive coating is periodically removed with a filter cake of dust that forms during the course of the dedusting on the filtering and separation equipment portion of the dedusting apparatus; This removal is less expensive and less cumbersome than the removal of solid particles penetrated within the filtering and separation plant portion of the dust removal apparatus.

According to one embodiment, the addition of the additive is carried out in accordance with the loading of the contaminated gas. In this context, the amount of contaminants is measured and the proper addition of additives is caused and the proper addition of additives is increased if the threshold in natural gas or cleaning gas predefined by the operator is exceeded. In this context, natural gas may be understood to mean gas before dry cleaning, and cleaning gas may be understood to mean gas after dry cleaning. It is desirable that it can consider a single type of contaminant. According to a preferred embodiment, the type of reactant in the additive is selected based on the contaminants considered. As a result, it is possible to add a reagent that is optimally suitable for the contaminants in question. Thus, the cost of reactant consumption can be minimized, and the solid particles separated during dust removal can be reduced in large amounts. This simplifies the appropriate additional application.

If preliminary separation is carried out, according to one embodiment of the process according to the invention, additives are added to the gas stream before the start of dust removal after the preliminary separation. As a result, the removal of additives from the gas stream before dust removal is avoided. Otherwise, the period of time the additive stays in the gas stream is reduced compared to the separation during dust removal, so that the cleaning capacity of the additive will be used in smaller amounts. Since only additives are added to the gas stream after the preliminary cleaning, the material obtained during the preliminary separation does not contain any additives. Because of the lack of additives, these materials are particularly suitable for use. Since the material does not contain any additives, it is not necessary to consider any additives present in use. By way of example, this use may be a recirculation of at least a partial material into the process from which the gas being cleaned is produced. However, the material may be used in other processes.

If the gas to be cleaned is produced in the pig iron production unit during the production of pig iron or in the iron production unit during the iron production, the material obtained during the preliminary separation can be recycled back to the iron-containing dust-for example iron production or pig iron production. Contains valuable raw materials. If the gas to be cleaned is produced in a coal gasification plant, the material obtained during the preliminary separation contains carbon-containing dust-for example a valuable raw material that can be recycled back into the gas gasification plant.

Preliminary separation has the advantage that less loading occurs due to contact with the solid particles in the part of the plant through which the gas flows after the preliminary separation.

Accordingly, the process according to the present invention, in the operating state in the case of starting and stopping or disturbing the operation of the pig iron or iron production unit, the risk of seizure or blockage of the filtering and separation equipment parts of the dust removal device, in particular the risk of condensation. Because of this, while very large, the dust removal has the effect that it can be performed under less disruption when compared with the prior art. Thus, since dust removal and contaminant cleaning can be performed in this operating state, in fact, there is no longer a need to bypass the gas containing dust and contaminants through the bypass to the environment.

According to one embodiment, the additive consists of at least one of a reactant and an adsorbent; This is because additional components of the additive that do not act as reactants or adsorbents reduce the achievable effect of the additive per unit mass of the additive.

The granular dry additive added has a crystal size of 0.1 to 200 μm. The crystal size range ensures that the additive can be distributed homogeneously in the gas stream. If an important part of the crystal size falls out of this range, homogeneous distribution in the gas stream is difficult, which will lead to a low separation rate during dust removal. The smaller the crystal size of the additive, the larger its specific surface area. As the specific target increases, the reaction process with the contaminants, the adsorption of the contaminants, and the binding of the moisture become possible, which makes it possible to process more efficiently.

However, the price of the additive increases as the crystal size becomes smaller, so that the use of an additive having a crystal size of less than 0.1 μm is no longer economically rational. Off-gases from pig iron production units are generally at high pressures. The absolute pressure of off-gas from the pig iron production unit is between 2 x 10 ⁵ Pa and 6 x 10 ⁵ Pa, ie between 2 and 5 bar. This pressure must be overcome during the addition of the additive to the gas stream. This preferably takes place using pneumatic pressure injection of the additive. Alternatively, the drying additive may be introduced using gravity dosing, where it is sealed against the outside with excess pressure, for example using star feeders or dual rotary locks. It should be possible to ensure that it is sealed off. During the addition of the additive to the gas stream, it is essential to ensure that the additive is distributed homogeneously. This can be realized, for example, using a so-called static mixer (in the case of gravity administration) or an appropriate number of injection lances (in the case of pressure injection). The suspension can preferably be introduced using two fluid nozzles, where the liquid suspension is atomized using gas or steam.

Filtering and Separation Solid particles which are separated during dust removal in the dust removal apparatus are periodically removed from the apparatus. Solid particles that are separated may also react with contaminants still present in the off-gas, which may absorb contaminants, or bind moisture. Additives.

Thus, according to one embodiment of the process according to the present invention, the partial amount of solid particles separated during the dust removal as filter cake is added to the gas stream before the start of the dust removal when the further preliminary cleaning is completed. Recycling the additive into the gas stream increases the effect achievable per unit amount of additive; This is because reaction, absorption and moisture binding potentials that have not yet been used after the first addition of a significant amount of additive can be used after the fresh addition to the gas stream. Compared to a process without recirculation, it is thereby possible to achieve the same effect with less fresh additives, thereby reducing the filter cake to be automatically removed in a significant amount. Because of the pressure of the off-gas, the addition is preferably carried out using pneumatic pressure injection, but may also be carried out using gravity administration, for example.

Solid particles separated by filtering and separation dust removal devices also include carbon carriers and iron-containing dusts such as carbonaceous furnaces, coke ovens, Sorbalit® and ore-containing dusts. According to an advantageous embodiment of the process according to the present invention for the use of such materials in the production of pig iron or in the production of iron or coal gasification, at least a partial amount of solid particles separated during preliminary separation and / or dust removal as filter cakes Is used as starting material for the production of pig iron or for the production of iron or for gases produced in coal gasification plants. This improves its economic viability and allows the use of separated solid particles in a simpler way than when disposed of. However, as an example, such materials may be used after the pretreatment step in the steel production process (converter, electric furnace) or in the sintering process.

According to one embodiment of the process according to the present invention, the temperature of the gas stream from which dust is removed is set using an evaporative cooler. This has the advantage that even for a relatively long period of time the temperature can be adjusted in a stable manner to the desired temperature.

According to another embodiment of the process according to the present invention, the temperature is set using a plate-shaped heat exchanger. This has the advantage that there is no additional injection of water to be provided and the average gas temperature or sensible heat of the gas is higher. In one example, this increases energy efficiency for subsequent use in a gas expansion turbine when compared to temperature settings with an evaporative cooler. In this case, there are generally two exemplary variations. One of them is guided via a heat accumulator only when the gas exceeds the maximum operating temperature (eg 260 ° C.) of the device performing the dust removal and again when the temperature is undershooted. Guided through, and the other is the two plate-shaped heat exchangers connected in parallel. If the discharge temperature of one heat accumulator exceeds the maximum operating temperature, it is switched to another heat accumulator, for example a hot heat accumulator additionally cooled with ambient air.

Coal gasifiers, which can be designed as fixed-bed gasifiers or entrained-flow vaporizers, are characterized by their properties, particularly from pig iron and iron production units, for dust loading and contaminant loading. Produces a gas that is comparable to that of The gas from the coal gasification plant is used as reducing gas, inter alia, during the production of pig iron or iron. According to one embodiment of the process according to the present invention, the gas from which the dry dust removal and dry cleaning is carried out comes from a coal gasification plant.

The process according to the present invention comprises a feed line for directing a gas stream from a pig iron production unit, or an iron production unit, a coal gasification plant, in which a preliminary separation device is located, the feed line being at a branch point. Divided into a primary gas line comprising a bypass line and one or more degassing devices, the primary gas line being connected to the degassing devices via a connecting line, the apparatus for setting the temperature of the gas stream And using an apparatus located upstream of the gas removal apparatus in the gas line or primary gas line.

The device has a device for adding an additive in the primary gas line, and the device for adding an additive is located between the branch point and the first connection line when viewed from the branch point.

In one example, the off-gas, pig iron production unit to be freed from dust and to be cleaned may be a blast furnace, a reduction shaft or a melt gas furnace associated with COREX® and FINEX® processes.

In one example, the iron production unit may be a MIDREX® plant, a HYL® plant, or a direct reduction plant based on COREX® or FINEX® exhaust gas.

The feed line leading the gas stream from the pig iron production unit or the iron production unit is connected with the pig iron production unit or the iron production unit.

Preliminary separation devices include, for example, gravity settling chambers, cyclones, Hurriclon® or electrostatic filters. Such devices can be used to efficiently separate coarse solid particles from a gas stream. The dust removal device comprises, for example, a round filter with a filter bag of woven fiber, ceramic or metal fiber. Such devices can be used to efficiently separate very fine solid particles smaller than 10 μm from a gas stream. This type of preliminary separator and dust removal device can operate at the pressure of the gas from which dust is removed.

According to one embodiment of the device according to the invention, the device for setting the temperature of the gas stream is located between the preliminary separation means and the dust removal device.

According to one embodiment of the plant according to the present invention, the device for adding particulate dry additive is a device for pneumatic pressure injection. According to another embodiment of the plant according to the present invention, the device for adding an additive is a device for gravity administration.

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

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

According to a further embodiment of the device according to the present invention, the solid particle line is derived from the device for removing the separated solid particles, and when viewed from a branch point in the bypass line and the primary gas line, or the flow of the gas stream When viewed from the direction, it goes to the primary gas line upstream of the first connection line. The further point is advantageously provided with a device for pneumatic pressure injection, in which solid particles can be introduced into the primary gas line against the pressure of the gas stream.

According to a further embodiment of the device according to the present invention, the additional line is derived from the device for removing the separated solid particles and / or from the device for removing the separated solid particles from the preliminary separation means, and the production of pig iron Proceed to the device for adding material to the unit or to the iron production unit.

According to a further embodiment of the device according to the present invention, the device for setting the temperature of the gas stream is an evaporative cooler.

According to another embodiment of the device according to the present invention, the device for setting the temperature of the gas stream comprises a heat exchanger in the form of a plate or other types of heat exchanger such as tube bundles, enhanced cold air coolers, and Ljungstrom heat exchangers. do.

According to a further embodiment of the device according to the present invention, the device for setting the temperature of the gas stream comprises a burner. The burners-generally with simple equipment and in an easy controlled way-are capable of rapidly increasing the temperature of the gas stream above the lower limit of 60 ° C. The fuel supplied to the burners is a combustible gas or a combustible gas mixture. It is preferred to use at least a portion of the dry dedusted and dry cleaned gas obtained in the process according to the invention as fuel for the burner.

According to the present invention, the feed line directs the gas stream from the coal gasification plant connected to the feed line.

The invention also provides for the use of energy present in the gas—for example, for expansion turbines—or for use of energy present in gas components for producing electricity in downstream turbines in dust removal and cleaning processes. The aim of simplifying – for example in chemical processes – is also achieved.

This use is simplified using the cleaning and dust removal according to the present invention, which means that the plant parts employed for this use are subjected to attack, for example, by solid particles and contaminants, which are subject to friction and corrosion. This is because they are exposed in a small range.

If heated-for example by a burner-it is necessary to set the temperature of the gas stream, which recovers the thermal energy supplied to the process at least partly in the use of thermal energy of the downstream gas of dust removal and cleaning. ) There is a profit.

In one example, the top gas has a specific calorific value of about 1.4 kJ / Nm ³ K-heating of about 500 000 Nm ³ / h requires about 200 kW / K of thermal power. In order to heat from 60 ° C. to 100 ° C., a thermal power of 200 * 40 = about 8 MW is required, which must be applied, for example by a burner or heat exchanger. Its about 10 MW can be recovered using a TRT gas expansion turbine.

Similarly, the present invention achieves the object of making solids present in the available gases and other materials carried along in the gas, since the materials obtained during preliminary separation, dust removal and cleaning can be obtained separately from one another. to be.

The supply line 1 shown in FIG. 1 leads a gas stream of gas produced in the pig iron production unit (not shown) to which the supply line 1 is connected during the production of pig iron. In the preliminary separation device 2, in this case a cyclone is located in the supply line 1. Coarse solid particles that are separated during preliminary separation with a crystal size of 10 to 200 μm can be removed from the cyclone, which is shown by the arrows derived from the cyclone. The material removed from the cyclone does not contain any additives. It comprises iron-containing dust-valuable raw materials-which is particularly suitable for introduction into iron production units (not shown) by the lack of additives. Since the material does not contain any additives, if this introduction occurs, no additives are introduced into the pig iron production unit. The supply line 1 splits into a bypass line 4 and a primary gas line 6 which lead from the branch point 3 to the chimney 5. The primary gas line 6 is connected with three connecting lines 7, 8, 9 leading to respective dust removal devices 10, 11, 12. The gas stream which has already been preliminarily separated is led to the dust removal devices 10, 11 and 12 via the primary gas line 6 and the connecting lines 7, 8 and 9. The temperature of the gas stream which is led out of the preliminary separator. The device for setting the device is in this case connected in parallel to the plate-shaped heat exchangers 21a, 21b device between the preliminary separation device 2 and the branch point 3 in the primary gas line 6. If the discharge temperature of one plate-type heat exchanger exceeds the maximum allowable gas temperature for the dust removal device, it is hot with another plate-type heat exchanger, for example in the meantime with additional cooling to ambient air. Switching takes place with a heat exchanger in the form of a flat plate An additional device for setting the temperature of the gas stream which is directed out of the preliminary separation device is that in this case the gas stream is water and / or further suspension. The evaporative cooler 13, which is treated with a furnace, is placed between the preliminary separation device 2 and the dust removal devices 10, 11, 12 in the primary gas line 6. A device 14, in this case a device for pneumatic pressure injection, is located in the primary gas line 6. The device is located downstream of the plate-shaped cooler and upstream of the evaporative cooler. The dust removal apparatus 10, 11, 12 includes an apparatus for removing the separated solid particles 15, 16, 17. The separated solid particles are separated from the solid particle line during the dust removal. A solid particle line 18 is added from the apparatus, as shown from the branch point 3 or in the direction of flow of the visible stream, via (18) and the first gas line (7). Primary gas line (6) upstream of Proceeds to Additionally occurs using a device (not shown herein) for the pneumatic pressure injection.

The gas produced in the pig iron production unit during the production of pig iron or the gas produced in the iron production unit during the production of iron and cleaned and dedusted according to the present invention is carried out in a downstream process of dust removal, for example in a coal drying plant or It can be used thermally in fine coal drying plants, steam power plants or gas and steam power plants. It can also be used as a reducing gas in an internal process during the production of pig iron or iron, for example after gas treatment by CO ₂ reforming or CO ₂ removal with natural gas, and recycled back into the process for production of pig iron or iron. Can be. In the embodiment of the present invention shown in the figures, degassed and cleaned gas is used in the downstream process. The off-gas, which has been dedusted and at a pressure of 2-6 x 10 ⁵ Pa, ie from 2 to 6 bar, has a gas expansion turbine (TRT) 20 via an exhaust line 19 leading to all dust removal devices. Guided by). In the gas expansion turbine, the off-gas pressure energy is used to produce electricity. The gas stream is led through the bypass line 5 to the dust removal device only in case of operational disturbances.

FIG. 2 shows the apparatus shown in FIG. 1 with the following differences compared to FIG. 1. There is no evaporative cooler. An apparatus 22 is shown for removing the separated solid particles from the preliminary separation means. For the sake of clarity, FIG. 2 does not show the point where the device goes from the point where the gas stream is derived to the device for the additive material of the pig iron production unit. As shown in the flow direction of the gas stream, upstream of the heat exchangers 21a and 21b in the form of a plate, there is a burner 23 in the supply line 1 as part of an apparatus for setting the temperature of the gas stream. For energy use and for conversion to electric power, the thermal energy supplied by the burners is used to some extent within the gas expansion turbine, downstream units for utilizing the thermal energy of the cleaned and degassed gas. This makes the process more economical.

1 supply line
2 spare separation device
Three quarter point
4 bypass lines
Five chimneys
6 primary gas lines
7, 8, 9 connection lines
10, 11, 12 Dust Removal Device
13 Devices for setting the temperature of the gas stream
14 Devices for adding additives
15, 16, 17 Device for removing separated solid particles
18 solid particle lines
19 exhaust lines
20 Gas Expansion Turbine (TRT)
21a, 21b flat heat exchanger
22 Devices for removing separated solid particles from preliminary separation means
23 burner

Claims (17)

Dry cleaning of the gas, including dust and contaminants, such as gas produced in the pig iron production unit during the production of pig iron, or gas produced in the iron production unit during the production of iron, or gas produced in the coal gasification plant And for the dry removal of dust from gases,
In the above process,
The gas stream consisting of the gas is subjected to dust removal after the preliminary separation for the separation of the coarse solid particles, during which the solid particles present in the gas stream in which the preliminary separation has already been separated are separated from the gas stream,
The temperature of the gas stream prior to dust removal is such that the temperature of the gas stream is at least 60 ° C., preferably at least 100 ° C., and below the temperature at which damage is caused to the apparatus performing the dust removal. Is set,
An additive comprising a reactant and, if appropriate, an adsorbent is added to the gas stream prior to the start of the dust removal,
fair. The method of claim 1,
And said additive is added to said gas stream using pneumatic pressure injection. The method of claim 1,
Wherein said additive is added to said gas stream using gravity dosing. 4. The method according to any one of claims 1 to 3,
When the preliminary separation ends, before the start of the dust removal, an amount of a portion of the solid particles separated during the dust removal is added to the gas stream, preferably using pneumatic pressure injection. Process. The method according to any one of claims 1 to 4,
Wherein an amount of at least a portion of said solid particles separated during said preliminary separation and / or dust removal is used as starting material for the production of pig iron or for the production of iron. The method according to any one of claims 1 to 5,
Wherein an amount of at least a portion of said solid particles separated during said preliminary separation and / or dust removal is used as starting material for the gas produced in the coal gasification plant. The method according to any one of claims 1 to 6,
Temperature of the gas stream is set prior to removing the dust using an evaporative cooler. The method according to any one of claims 1 to 6,
The temperature of the gas stream is set prior to the dust removal using a heat exchanger in the form of a plate. An apparatus for performing a process according to any one of claims 1 to 8,
A feed line 1 for directing a gas stream from a pig iron production unit, or an iron production unit, or a coal gasification plant, in which a preliminary separation device 2 is located, the supply line (1) splits at the branch point (3) into the bypass line (4) and the primary gas line (6),
The primary gas line 6 comprises one or more degassing devices 10, 11, 12,
The primary gas line 6 is connected to the degassing devices 10, 11, 12 via a connection line 7, 8, 9,
An apparatus 13 for setting the temperature of the gas stream is located upstream of the gas removal apparatus 10, 11, 12 in the primary gas line 6 or in the supply line 1,
There is an apparatus 14 for adding an additive in the primary gas line, and the apparatus 14 for adding the additive, when viewed from the branch point 3, has the branch point 3 and the first agent. It is characterized in that it is located between one connecting line (7, 8, 9),
Device. 10. The method of claim 9,
The device (14) for adding said additive is a device for pneumatic pressure injection. 10. The method of claim 9,
The device (14) for adding said additive is a device for gravity administration. 12. The method according to any one of claims 9 to 11,
The dust removal device (10, 11, 12) comprises a device (15, 16, 17) for removing the separated solid particles. 12. The method according to any one of claims 9 to 11,
Said preliminary separating means (2) comprising an apparatus (22) for removing solid particles separated from said preliminary separating means. The method of claim 13,
A solid particle line 18 is derived from the apparatus 15, 16, 17 for removing the separated solid particles and, when viewed from the branch point 3, upstream of the first connecting line 7. Apparatus characterized in that it advances to the primary gas line (6) of. The method according to claim 13 or 14,
An additional line is derived from the apparatus 15, 16, 17 for removing the separated solid particles and / or from the apparatus 22 for removing the separated solid particles from the preliminary separation means and producing the pig iron Apparatus for advancing to a unit or apparatus for adding material to the iron production unit. 16. The method according to any one of claims 9 to 15,
The apparatus (13) for setting the temperature of the gas stream comprises an evaporative cooler and / or a heat exchanger (21a, 21b) in the form of a plate. 16. The method according to any one of claims 9 to 15,
The device (13) for setting the temperature of the gas stream comprises a burner (23).

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