SK50162011U1 - Device for separating dust and dry-cleaning gas in the manufacture of iron or coal gasification - Google Patents

Abstract

The apparatus includes a feed line (1) for conducting a gas stream from a pig iron production unit or an iron production unit in which the separator is provided (2). The supply line (1) is branched at the branch (3) to the bypass line (4) and to the primary gas line (6). The device comprises at least one dust removal device (10, 11, 12). The primary conduit (6) is connected to the dust removal device (10, 11, 12) via a connecting pipe (7, 8, 9). The gas flow temperature adjusting device (13) is arranged upstream of the dust removal device (10, 11, 12) in the feed line (1) or in the primary gas line (6). The device (14) for adding additives in the primary gas line (6) is located between the branch (3) and the first connecting line (7, 8, 9) as viewed from the branch (3).

Description

Dry dust separator and gas purifier for the production of iron or coal gasification

Technical field

The technical solution relates to a device for separating dry dust and for dry scrubbing gas containing dust and impurities such as gas produced in pig iron production units during the production of pig iron in production, or gas produced in iron production units during production of iron or gas produced in coal degassing plants.

BACKGROUND OF THE INVENTION

During the production of pig iron in the furnaces in the pig iron production units, for example in the blast furnace, the COREX® plant, the FINEX® plant and the melter gasification plant, or the iron production in the iron plant units, eg MIDREX® plant, HYL® plant and direct reduction (DR) devices based on the COREX® / FINEX® outlet gas, large amounts of gases are produced.

These gases carry large amounts of dust with a high fine solids ratio as well as large amounts of gaseous impurities.

Mostly during unstable operation, i. especially in operating situations such as starting or stopping processes for the production of pig iron, or iron, or spontaneous process anomalies such as spontaneous displacement of the column of material in units, in particular high amounts of dust and impurities in gases and high temperature peaks gas. The dust must be separated and the gas cleaned of impurities before the gases are discharged into the environment or used in the following processes.

By way of example, the properties of gases produced during the production of pig iron in blast furnace knots, COREX® equipment or FINEX® equipment are shown:

Blast furnace COREX® FINEX® Amount of gas 350 000- 250 000- 150 000- [Nm ³ / h] 750 000 400 000 350 000 Gas temperature 100-200; 300; 400-450; R c] max. 800 max. 600 max. 600 Gas pressure 250; 320 220-320; [KPa] max. 350 max. 600 Gas composition [% by volume] WHAT 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 Amount of dust in the produced 20 000 - 20 000 - 12 000- gas [mg / Nm ³ ] 25 000 25 000 37 000 Impurities in the produced gas [mg / Nm ³ ] HC1 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 remove dust and impurities from the gas produced in both wet and process processes, but such processes present the problem of the need to treat slurry and the scrubbing water formed therein.

Chinese patent application CN 1 818 080 describes a method for dry removal of dust from a gas stream coming from blast furnaces.

In this method, in a dry gas stream, dust is removed by means of a filter separator after preliminary dry separation in a separation chamber.

However, during operating situations outside the stable operation of the blast furnace, for example during start-up or shutdown, or where the outlet gas temperatures are below the dew point of the water or the acid dew point of moisture present in the gas stream, there may be a problem that the filter material of the separators is sticking together and can cause blockage, as the components carried simultaneously in the gas, for example water moisture or organic components, condense.

This leads to significant pressure losses in the filter material and also to filter efficiency losses, and it may be necessary to replace the filter material associated with the downtime.

If the equipment in which the dust removal is carried out is not available due to such problems, the dust-containing gas must be discharged into the environment through the bypass line without further purification.

Such a bypass situation creates environmental hazards and is not permissible in a number of industrialized countries.

In order to reduce the risk of sticking or blocking due to the drop in the gas temperature below the dew point and the associated condensates, CN 1 818 080 describes heat exchangers which, in the case where the temperature of the gas flow coming from the pre-separator is too high. low, they are used to raise the gas temperature above the dew point.

No measures for the purification of exhaust gases from impurities are given in CN 1 818 080.

SUMMARY OF THE INVENTION The object of the present invention is to provide a device for removing dust dry from the off-gases generated during pig iron production, which will reduce the risk of sticking and blocking of the off-dust filters while at the same time cleansing the off-gases.

The essence of the technical solution

This task has been accomplished by developing a method for removing dry dust and purifying a gas containing dry dust and impurities such as the gas produced in the pig iron production units during the production of the pig iron in the production or the gas produced in the steel production. In such processes, a gas stream containing such a gas is subjected to dust removal after pre-separation to remove coarse solid particles, during this dust removal, the solid particles present in the process. in a gas stream which has already been subjected to a preliminary separation, preferably the gas stream is separated from the gas stream, wherein the temperature of the gas stream before removal of the dust stream is set such that the gas stream temperature is greater than 60 ° C preferably greater than 100 ° C, and less than the temperature it could cause damage to dust removal equipment.

The present method is characterized in that the additive-containing reagent, and optionally the adsorbent, is added to the gas stream prior to initiating dust removal.

In the exemplary case, the pig iron unit may be a blast furnace, a reduction shaft or a melter gasification plant in accordance with the COREX® or FINEX® process.

The solid or molten pig iron in the rolls or the primary steel product is produced in such units.

By way of example, the iron production unit may be a MIDREX® device, a HYL® device, or a COREX® / FINEX® outlet gas direct reduction device.

Sponge iron or briquetted iron is produced in such units.

During the preliminary separation, which is optionally carried out, the coarse solid particles entrained in the gas stream can be separated, for example in gravity chambers (dust bags) or in cyclones.

Coarse solid particles are to be considered as main solid particles having a particle diameter greater than 10 µm.

Since only coarse solid particles up to the lower limit of their order of magnitude are effectively separated in the preliminary separation, the solid particles that are below this lower limit are still present in the gas stream after the preliminary separation has taken place.

Such solid particles, containing 2.5 µm fine dust particles, and, if no pre-separation, as well as solid coarse particles, are removed from the gas stream during dust removal up to dust concentrations of 5 mg / Nm ³ .

When pre-separation is carried out, the temperature of the gas stream prior to dust removal is set according to one embodiment of the present method after pre-separation.

The temperature of the gas during the pig iron production or in the iron production fluctuates, for example depending on the process used or the occurrence of an unstable process state, for example in the case of a collapse of the material column in the reduction or melting shaft, or .

Dust removal occurs in filtering devices, such as fabric filters, made of glass fibers or synthetic fibers, such as Aramid® or P84® (polyimide fibers), having a circular type design, metal filters or ceramic filters.

In order to protect the dust removal devices from the condensation problems that cause the filter cake to stick off during dust removal and to the temperature peaks in the gas stream, the temperature of the gas stream before the dust removal and after any preliminary separation is set such that the temperature of the dust removal gas stream is greater than 60 ° C, preferably greater than 100 ° C, and less than the temperature that could cause damage to the dust removal devices.

In the case of fabric filters, the temperature must be less than 260 ° C, preferably less than 200 ° C, as the fabric filters decompose the filter fabric at a temperature greater than 260 ° C due to heat.

In the case of ceramic filters or metal filters, gas temperatures up to 1000 ° C can be used.

The gas produced during the production of pig iron in the units in the pig iron production units or the gas produced during the production of iron in the iron production units contains inter alia hydrogen sulphide, hydrogen chloride, hydrogen fluoride, heavy metals, organic impurities such as dioxins or furans, polycyclic aromatic and other hydrocarbon compounds.

These environmentally harmful compounds must be removed prior to the discharge of the waste gases into the environment as far as is economically feasible.

According to this invention, the particulate additives, the dry additives or the additives in the form of a suspension of additives in water are added to the gas stream before the dust removal is started.

The additives comprise reagents and, optionally, adsorbents.

The reagents are selected to react with impurities present in the off-gas from the pig iron production plant to form particulate products that can be removed from the gas stream by dust removal.

The reagents employed are, for example, CacO ₃ , Ca (OH) ₂ , Mg (OH) ₂ or sodium bicarbonate, or mixtures of two or more thereof.

The basic task of the reagent is to separate acidic contaminants such as H ₂ S, HCl or HF.

The additives may also contain organic and / or inorganic adsorbents, for example, hearth furnace coke (HOK), activated carbon or coke, or finely divided zeolite.

The impurities present in the waste gases, for example heavy metals or organic impurities, can be removed from the gas stream by adsorption through an adsorbent, where the adsorbent product containing the adsorption-containing impurities is particulate so that it can also be removed from the gas stream during dust removal.

The additive may also be a mixture of lime and carbon with additives, which is also known, for example, under the trade name Sorbalit®.

Particulate additives or particulate reaction products or particles or adsorption components of the ingredients are removed from the gas stream again during dust removal.

The additives may also be injected into the gas stream in the form of a suspension in water, for example as lime milk. A suitably high gas temperature of greater than 150 ° C is required for the addition of the additives in the form of a suspension.

When the additives are added to the gas stream in the form of a suspension, the liquid evaporates in the hot gas stream, as a result of which the additives can be removed as particulate dry additives in the dust removal.

Since cooling of the gas is also carried out when the additives are added in the form of a suspension, this type of addition can be associated with the process step in terms of gas temperature adjustment.

The addition of additives according to this invention has the advantage that the impurities present in the gas can be removed simultaneously with the removal of dust from the gas stream.

A further advantage is that both the reagent and the adsorption agent can bind the moisture present in the gas stream, thereby reducing the risk of moisture condensation from the gas stream.

A further advantage is that the additives or particulate products formed as a result of the reaction with the reagent or adsorption on the adsorbent are deposited in filtering and dust removal devices, which are then coated.

On the one hand, this coating of the additive, which contains a detached filter cake, contributes to the removal of dust because the gas stream must pass through it.

On the other hand, it prevents the filtering and separation of parts of the dust removal device, since the waste gas stream only encounters it when passing through the coating.

The risk of blocking or sticking of the filter and separator device parts in the case of a dust removal device is thus reduced, since the organic gas content of the gas stream or moisture and / or fine adhesive solid particles may already be partially separated in the filter cake.

The protection of the components thus achieved results in an increased service life.

The additive coating is regularly removed together with the dust filter cake that is formed during dust removal on the filter and separator device components of the dust separator.

This removal is less expensive and less complicated than removal of particulate matter that penetrates the components of the filter and separator device of the dust removal device.

According to one embodiment, the addition of the additives is carried out depending on the impurity content of the gas.

In this context, the impurity content is measured, with an appropriate amount of additives being added or increased if the thresholds in the unprocessed gas or the purified gas predetermined by the operator are exceeded.

In this context, the raw or unprocessed gas is considered to be the gas before dry scrubbing, and the purified gas is considered to be the gas after dry scrubbing.

It is preferred that individual types of impurities be detected.

According to a preferred embodiment, the type of reagent in the additive is selected based on the impurities detected.

It is therefore possible to add a reagent that is optimally suitable for the respective impurities.

Thus, the cost of consuming the reagent can be minimized, and the resulting amounts of solids separated during dust removal can be reduced.

This simplifies the appropriate further use.

If pre-separation is carried out, the additives are added to the gas stream according to one embodiment before the removal of the dust after the preliminary separation.

Removal of additives from the gas stream is thus not necessary even before dust removal.

Thus, the duration for which the additives remain in the gas stream can be reduced compared to separation during dust removal, while the corresponding cleaning capacity of the additives can also be used to a lesser extent.

Since the additives are added to the gas stream only after preliminary separation, the material obtained during the preliminary separation does not contain any additives. Due to the absence of additives, this material is particularly suitable for use.

Since the material does not contain any additives, it is also not necessary to consider any additives in the case of such use.

For example, recovery can be carried out at least partially recirculating the material into a 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 the pig iron production units during the pig iron production or in the iron production units during the iron production, the material obtained during pre-separation contains iron-containing dust, which is a valuable raw material, which can be recycled, for example, to pig iron production or iron production.

When the gas to be cleaned is produced in coal gasification plants, the material obtained during the pre-separation contains carbon-containing dust, a valuable raw material that can be recirculated back to the coal gasification plant, for example.

Pre-separation has the advantage that the components of the device through which the gas flows after the pre-separation are subjected to less fouling through contact with the solid particles.

The present method has the effect that dust removal can be accomplished by less interruption compared to the prior art, even in operating conditions such as start-up and shutdown, or in the case of operating failures of pig iron or iron production units during which the risk of blocking or sticking of filter and separator equipment components in dust removal equipment is particularly high due to the risk of condensation.

Since dust removal and dirt cleaning can also be carried out in such operating conditions, it is in fact no longer necessary to discharge the dust and dirt containing gas through the bypass line into the surrounding environment.

In one embodiment, the additives consist of one or both reagent and adsorbent components. This is because the additive ingredients that do not act as a reagent or adsorbent reduce the achievable effect of the additive per unit weight of the additive.

The particulate dry additive that is added has a particle size of from 0.1 to 200 µm. This grain size range ensures that the additive is evenly distributed throughout the gas stream.

If the significant grain size ratio is above this range, even distribution in the gas stream will be difficult, resulting in a low separation rate during dust removal.

The smaller the grain size of the additive, the greater its specific surface area. As the specific surface area increases, it is possible to provide a much more efficient process of reaction and adsorption of impurities as well as moisture binding.

However, the cost of the additives increases when the grain size is smaller, so that the use of additives having a grain size of less than 0.1 µm is no longer economically advantageous.

The off-gas from the pig iron production units usually has a high pressure. The absolute pressure of the off-gases from the pig iron production units is from 2 x 10 ⁵ Pa to 6 x 10 ⁵ Pa, ie from 2 to 5 bar.

This pressure must be overcome during the addition of the additive to the gas stream. This is preferably done by pneumatic injection of the additive.

As an alternative, the dry additive may also be supplied by gravity dosing, in which case it must be ensured that the excess pressure is sealed to the outside, for example by means of star feeders or double rotary locks.

During the addition of the additive to the gas stream, it must be ensured that the additive is supplied and distributed evenly. This can be done, for example, using a so-called static mixer (in the case of gravity dosing) or a suitable number of injection tubes (in the case of pressure injection).

The suspensions are preferably supplied by means of double fluid nozzles, the liquid suspensions being atomized by gas or vapor.

The solid particles that are separated during dust removal in the filtering and dust removal devices are regularly removed from the plants.

The separated solid particles also contain additives which can still react with the impurities present in the waste gases, absorb the impurities or bind moisture.

Accordingly, according to one embodiment of the present invention, a partial amount of solids separated during dust removal as a filter cake is added to the gas stream prior to commencing dust removal after completion of any pre-separation.

This recirculation of the additives to the gas stream increases the achievable effect per unit amount of the additive.

This is because the potentials for the reaction, adsorption and binding of moisture, which remain unexploited after the first addition of the first additive, can be exploited after the new addition to the gas stream.

Compared to a process without recirculation, it is therefore possible to achieve the same effects with less fresh ingredient, which automatically reduces the size of the filter cake that has to be removed.

Due to the waste gas pressure, the addition is preferably carried out by pneumatic pressure injection, but can also be carried out, for example, by gravity dosing.

The solid particles separated by a dust removal filter and removal device also contain carbonaceous carriers such as coal dust, hearth coke (HOK), Sorbalit® and ore-containing dust and iron-containing dust.

For the use of this material in pig iron production or in iron production or in coal gasification according to a preferred embodiment of the present invention, at least a partial amount of solid particles separated during preliminary separation and / or dust removal as a filter cake is used as a starting material for production pig iron in slabs or for the production of iron or for gas produced in coal gasification plants.

This improves their economic life and the use of the separated solid particles in a simpler way than their disposal.

However, the material can, for example, also be used after optional pretreatment steps in steel production (converter, electric furnace) or sintering.

According to one embodiment of the invention, the temperature of the dust removal gas stream is adjusted by means of a firing cooler. This has the advantage that the temperature can be regulated in a stable manner to the desired temperature, even for a relatively long period of time.

According to another embodiment of the present invention, the temperature is adjusted by means of a plate type heat exchanger. This has the advantage that no additional water injection has to be carried out and that the main gas temperature or the apparent heat of the gas is higher.

This increases, for example, the energy efficiency for subsequent use in a gas expansion turbine compared to a temperature setting by means of a firing cooler.

In this case there are generally two variants of the embodiment.

Either the gas is passed through the heat accumulator only when the maximum operating temperature of the dust removal devices (e.g. 260 ° C) is exceeded and is routed through the heat accumulator again where this temperature drops, or two other plate-type heat exchangers are connected parallel.

If the outlet temperature of one heat accumulator exceeds the maximum operating temperature, it is switched to the other heat accumulator, while the upper accumulator is in the meantime cooled further by, for example, ambient air.

Coal gasification plants, which may be designed, for example, as a fixed bed gasifier or a entrained gasifier, produce gas comparable in terms of its properties, in particular in terms of dust content and gas impurity content, from pig iron production units and for the production of iron.

The gas from the coal gasification plant is used, inter alia, as a reducing gas during the production of pig iron or steel.

According to one embodiment of the present invention, the gas subjected to dry dust removal and dry cleaning is derived from a coal gasification plant.

The apparatus according to the invention comprises an inlet pipe for guiding a gas stream from a pig iron production unit or from an iron production unit or from a coal gasification plant in which there is a preliminary separator device, wherein the inlet pipe is branched at the branching point of the bypass and a primary gas line comprising at least one dust removal device, wherein the primary gas pipe is connected to the dust removal device by means of a connecting line, wherein the gas flow temperature adjusting device is arranged downstream of the dust removal device in the supply line or in the primary gas line.

The subject apparatus is characterized in that there is an additive addition device in the primary gas line, wherein the additive addition device is located between the branching point and the first connecting pipe, as seen from the branching point.

For example, the pig iron production unit from which the exhaust gas to be cleaned and de-dusted may be a blast furnace, a reduction shaft or a melter gasifier in accordance with the COREX® or FINEX® process.

For example, the iron production unit may be a MIDREX® device, a HYL® device, or a COREX® / FINEX® exit gas direct reduction device.

A supply line that feeds a gas stream from the pig iron unit or from the iron production unit is connected to the pig iron unit or to the iron production unit.

The pre-separation device comprises, for example, a gravity settling chamber, a cyclone, a Hurriclon® or an electrostatic filter. These devices can be used for efficient separation of coarse solid particles from the gas stream.

The dust removal device comprises, for example, a circular filter with filter bags of textile fabric, ceramic or metal fabric. Such devices can be used to efficiently separate extremely fine particulate matter smaller than 10 µm from the gas stream.

Pre-separation and dust removal devices of this type are capable of operating at the pressure of the gas from which the dust is to be removed.

According to one embodiment of the device according to the present invention, the gas flow temperature adjusting device is located between the preliminary separator device and the dust removal device.

According to one embodiment of the device of the present invention, the particulate dry additive device comprises a pneumatic pressure injection device.

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

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 pre-separation device comprises a device for removing the separated solid particles from the pre-separation device.

According to a further embodiment of the apparatus according to the present invention, the particulate line extends from the particulate separation device and flows into the primary gas line upstream of the first connecting line when viewed in the downstream direction or viewed from the branching point in the bypass line and primary. gas pipe.

The orifice is preferably provided with a pneumatic injection molding device by means of which the solid particles can be supplied to the primary gas line against the pressure of the gas stream.

According to a further embodiment of the apparatus according to the present invention, the auxiliary piping starts from the separated solids removal device and / or the separated solids removal device from the preliminary separator device and opens to a material addition device to the pig iron unit or to the unit. for the production of iron.

According to another embodiment of the apparatus according to the present invention, the apparatus for adjusting the temperature of the gas stream comprises an evaporator cooler.

According to another embodiment of the apparatus according to the present invention, the gas flow temperature adjusting apparatus comprises a plate type heat exchanger or other types of heat exchangers such as tube bundles, forced air coolers and Ljungstrom type heat exchangers.

According to another embodiment of the device according to the present invention, the air flow temperature setting device comprises a burner.

The burner makes it possible to quickly raise the temperature of the gas stream above the 60 ° C lower limit, generally by simple equipment and in an easily controllable manner.

The fuel supplied to the burner is a combustible gas or a combustible gas mixture.

It is preferred to use at least some of the dust-free dry and cleaned dry dust obtained in the process as a fuel for the burner.

According to another embodiment of the apparatus according to the present invention, the inlet pipe feeds a gas stream from the coal gasification apparatus connected therein.

The present invention also fulfills the task of simplifying the use of the energy present in the gas, for example, to generate electricity in a turbine after performing a dust removal and purification process, for example in an expansion turbine, or in gas components, for example in chemical processes.

Such use is simplified by the cleaning of dust removal according to the present invention, since the parts of the apparatus used for these uses are exposed to a lesser extent to particles and impurities, which may have, for example, abrasive and corrosive properties.

If heating, for example by means of a burner, is necessary to adjust the temperature of the gas stream, it is preferable to regenerate the thermal energy supplied to the process, at least in part, by utilizing the thermal energy of the gas downstream of dust removal and scrubbing.

For example, the top gas has a specific heat capacity of about 1.4 kJ / Nm K, while heating of about 500,000 Nm ³ / h requires a heating energy of about 200 kW / K.

In order to heat from 60 ° C to 100 ° C, 200 x 40 = about 8 MW of heating energy is needed, and this energy must be supplied, for example, by a burner or heat exchanger.

About 10 MW of this energy can be recovered using the TRT gas expansion turbine.

Similarly, this technical solution fulfilled the task of utilizing solids present in the gas and other substances entrained in the gas, since the materials obtained during preliminary separation, dust removal and purification are obtained independently of each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and schematically in the accompanying drawings, which will be explained on the basis of the following description.

Fig. 1 shows a device according to the invention.

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

Examples of technical solution

The supply line 1 shown in FIG. 1, conducts a stream of gases produced in the pig iron production unit (not shown) to which the supply line i is connected during the pig iron production.

The preliminary separation device 2, in this case a vortex duster or a cyclone, is arranged in the supply line 1.

The coarse solids separated during the pre-separation and having a grain size of from 10 to 200 µm can be removed from the cyclone, as shown by the arrow starting from the cyclone.

The material removed from the cyclone does not contain any additives. This material contains iron-containing dust, which is a valuable raw material which, due to the absence of additives, is particularly advantageous for feeding to a pig iron production unit (not shown).

Since the material contains no additive, there is no additive fed to the pig iron unit, if such feed occurs.

The inlet pipe 1 branches at a branch point 3 into a bypass pipe 4 which leads to a chimney 5 and a primary gas pipe 6.

The primary gas line 6 is connected to three connecting lines 7, 8 and 9 which lead to respective dust removal devices 10, 11 and 12. The gas stream which has already been subjected to preliminary separation is passed through the primary gas line 6 and through the connecting lines 7, 8 and 9 to the dust removal devices 10, 11 and 12.

A device for adjusting the temperature of the gas stream discharged from the pre-separation device, in this case the plate-type heat exchangers 21a and 21b, connected in parallel, is arranged between the pre-separation device 2 and the branching point 3 in the primary gas line 6.

If the outlet temperature of one plate-type heat exchanger exceeds the maximum allowable gas temperature for the dust removal device to switch to another plate-type heat exchanger, the plate-type heat exchanger is in the meantime further cooled by, for example, ambient air.

A further device for adjusting the temperature of the gas stream discharged from the pre-separation device, in this case an evaporator cooler 13 in which the gas stream is treated with water and / or additive suspension, is arranged between the pre-separator 2 and the devices 10, 11 and 12. removal of dust in the primary gas line.

In addition, the particulate dry solid additive 14, in this case the pneumatic injection molding device, is arranged in the primary gas line 6.

This device is arranged downstream of the plate-type cooler and upstream of the evaporative cooler. Addition of the ingredient is symbolized by an arrow.

The dust removal devices 10, 11 and 12 comprise devices 15, 16 and 17 for removing the separated solid particles. The solids separated during the dust removal are added to the gas stream via the particulate line 18 which exits the apparatus and leads to the primary gas line 6 upstream of the first connecting line 7, as seen in the direction of gas flow or from the branching point 3 . The addition is carried out using a pneumatic pressure injection device (not shown).

The gas which is produced in the pig iron production units during the pig iron production or in the iron production units during the iron production and is dust-free and cleaned can be thermally utilized in downstream processes for dust removal, for example in wind heaters, coke ovens, raw material drying plants, for example in coal-drying plants or fine-coal-drying plants, in steam power stations or in gas and steam power stations.

It can also be used in internal processes to produce pig iron or steel as a reducing gas after gas treatment, for example by reforming CO ₂ with natural gas or removing CO2 and can be recirculated back to the pig iron or iron production process.

In carrying out the technical solution shown in the figure, the dust is cleaned and the cleaned gas is used in a further process. The off-gas that has been subjected to dust removal and is at a pressure of from 2 to 6 x 10 ⁵ Pa, i.e. from 2 to 6 bar, is fed to the gas expansion turbine (TRT) 20 via an outlet duct 19 which leads to all removal devices. dust.

In this gas expansion turbine, the pressurized energy of the off-gas is used to generate electricity. The air flow is conducted through the bypass duct 4 only in the event of an operating failure of the dust removal device.

In FIG. 2 shows the device shown in FIG. 1, but with the following differences from FIG. First

There is no evaporator cooler. A device for removing the separated solid particles from the preliminary separator device 22 is shown here.

For the sake of clarity, FIG. 2 shows the point at which the device opens to a material feed device to the pig iron production unit from which the gas stream flows.

In the flow direction upstream of the plate type heat exchanger 21a and 21b, viewed in the flow direction of the gas stream, a burner 23 is provided in the supply line 1 as part of the gas flow temperature setting device.

The thermal energy supplied by the burner is utilized to some extent in the gas expansion turbine, downstream, to utilize the clean and dust-free thermal energy of the gas, to be converted to electricity and for energy recovery. As a result, the process is much more economical.

Claims (9)

PROTECTION REQUIREMENTS Apparatus comprising a supply line (1) for conducting a gas stream from a pig iron unit or a iron unit in which there is a preliminary separator device (2), wherein the supply line is branched at a branch (3) for a bypass line (4) and a primary gas line (6) comprising at least one dust removal device (10, 11, 12), the primary line (6) being connected to the dust removal device (10, 11, 12) via a connecting line (7, 8, 9), wherein the gas flow temperature adjusting device (13) is arranged downstream of the dust removal device (10, 11, 12) in the supply line (1) or in the primary gas line (6). ), characterized in that there is an additive addition device (14) in the primary gas line, wherein the additive addition device (14) is located between the branching point (3) and the first coupling piece (3). piping (7, 8, 9) as seen from the branch point (3). Device according to claim 1, characterized in that the additive adding device (14) is a pneumatic injection molding device. Apparatus according to claim 1, characterized in that the additive addition device (14) is a gravity dosing device. Device according to one of Claims 1 to 3, characterized in that the dust removal device (10, 11, 12) comprises a device (15, 16, 17) for removing the separated solid particles. Device according to one of Claims 1 to 3, characterized in that the pre-separation device (2) comprises a device (22) for discharging the separated solid particles from the pre-separation device (2). Apparatus according to claim 5, characterized in that the particulate line (18) extends from the particulate removal device (15, 16, 17) and flows into the primary gas line (6) downstream of the first connecting line (18). 7) viewed from the branch point (3). Apparatus according to claims 5 and 6, characterized in that the auxiliary piping extends from the separated particulate matter removal device (15, 16, 17) and / or from the separated particulate matter removal device (22) from the preliminary separation device and leads to a material addition plant to a pig iron unit or to an iron unit. Apparatus according to one of claims 1 to 7, characterized in that the device (13) for adjusting the temperature of the gas stream comprises an evaporative cooler and / or a plate type heat exchanger (21a, 21b). Device according to one of Claims 1 to 7, characterized in that the gas flow temperature setting device (13) comprises a burner (23).