KR101946343B1 - Method for producing pressed articles containing coal particles - Google Patents

Abstract

Compression in a method for producing a compact containing coal particles, a compact obtained thereby and a method for producing pig iron in a fixed bed or a method for producing a carbon carrier for a method for producing pig iron in a fixed bed Lt; / RTI > To this end, a portion of the coal particles treated with the compact is impregnated with the desired material before the material treated with the compact is mixed with the binder system containing water, and finally compacted with the compact.

Description

METHOD FOR PRODUCING PRESSED ARTICLES CONTAINING COAL PARTICLES FIELD OF THE INVENTION [0001]

The present invention relates to a process for producing a compact containing coal particles, a compact obtained thereby and a method for producing a pig iron in a fixed bed or a method for producing a carbon carrier for a process for producing pig iron in a fixed bed Lt; / RTI >

For example, it is possible to produce carbon carriers for the production of pig iron in a fixed bed of a melter-gasifier or for producing pig iron in a fixed bed, for example coal particles used in a process for producing coke for a furnace The compacts containing, for example, the blast furnace, must have a specific shatter strength and compressive strength after discharge from the press. The drop strength can be maintained, for example, in a wide range as far as possible during charging to any process, regardless of the inevitable drop in conveyance from one conveyor belt to another conveyor belt or upon filling into a material reservoir . The compressive strength is necessary to ensure that the original size of the compact is retained after filling into the material reservoir or fixed bed reactor, despite the pressure generated by the superposed layer of material. The requirements for these strengths are also encompassed under the term cold strength.

In addition to the low temperature strength, the hot strength of the compact, especially during use in heat treatment, is a criterion for suitability for use. In a specific use of the compact containing the fine-grained coal particles in a process for producing pig iron, such as, for example, in a melter-gasifier or furnace, the term high temperature strength means a) after pyrolysis of the compact in the hot zone The intensity of the residual coke or coke particles, and b) the strength of these coke or coke particles due to chemical attack by the hot CO ₂ -containing gas. The minimum level of high temperature strength allows most of the size of these particles to be retained after the compact is converted to coke or coke particles by pyrolysis. In the case of a process for producing pig iron in a fixed bed, the growth of small materials from the coke particles, or compacts, into the fixed bed, or before filling in the fixed bed, may cause this growth to become a factor that worsens the permeability of the fixed bed Which is undesirable. In the case of special methods for producing pig iron, this affects both the gas permeability and the drainage behavior of the fixed bed against liquid pig iron and slag. If the permeability of the fixed layer deteriorates, it will have a negative impact on productivity, non-energy requirements and product quality.

It is known from WO 02/50219 A1 to produce compacts having sufficient low temperature strength from fine-grained coal particles by means of a binder system comprising quicklime and molasses. This method comprises the steps of mixing granular coal particles of pulverized coal and quicklime, leaving the mixture intact for the purpose of advancing a slaking reaction with moisture from the coal particles, then mixing the mixture with molasses, And finally compressing the compact therefrom.

There is a coal which exhibits very high water absorption and is characterized by a particularly high intrinsic moisture content. However, for use in the production of pig iron, the moisture content of the compact should not be too high. That is, it should be not more than 7% by weight. This is because when the compact is used to produce a carbon carrier for producing pig iron or for producing a pig iron, the consumption rate of the carbon carrier increases significantly with the moisture content of the compact, so that this moisture depletes the energy Because. Therefore, coal having a moisture content higher than this should be dried before being compressed into a compact. In addition to the wet pore volume already present in the un-dried coal, additional pore volume is created by removing water from the cavity during drying. The untreated pore volume can absorb a corresponding amount of water or a water-containing medium. Obviously, the additional pore volume can also absorb water or moisture-containing media once more. In addition, certain coals tend to produce additional pore volume as a result of particle damage, especially in the case of intensive drying. Prior to the application of the process described in WO 02 / 50219A1 to produce compacts, drying of coal with high water absorption properties to an acceptable water content results in an additional large pore volume. Thus, the dried coal particles suck into the pores a significant amount of molasses which is necessary to establish a bond to the particle surface and which can be regarded as an aqueous solution. Thus, as used conventionally, it is impossible to obtain sufficient strength of the compacts for such coal by adding molasses of < 10 wt%, based on the weight of coal to be treated. Nevertheless, in order to be able to produce a compact having sufficient strength based on a molasses binder,

- eliminating the generation of untreated pore volume by drying,

- It is necessary to add as much additional molasses as possible that is not available for bonding to the surface of the coal particles, which is occupied by the pore volume.

However, such measures are undesirable for reasons of process economy.

Even in the case of coal which naturally has minimal moisture and does not need to be dried to obtain a moisture content of up to 7% by weight of the compacted matter, part of the molasses is sucked into the pores of the coal particles. However, the molasses contains a component which catalyzes the reaction of carbon with a hot CO ₂ -containing gas, and thus the extent of the reaction of CO ₂ and solid carbon with the boudouard reaction depends on the pressure Especially in the high temperature region of the fixed bed used to produce pig iron at temperatures of> 800-1000 < 0 > C. As a result, the high-temperature strength of the recycled coke or coke particles obtained by pyrolysis from molasses-treated compacts decreases.

The use of bitumen as the binder proposed in WO9901583A1 does not present this type of problem with molasses. However, the production of compacts by biting is associated with a very expensive binder cost.

The use of an aqueous bituminous tanning agent as the binder system proposed in AT005765U1 reduces the consumption of bitumen by up to 50% or more. However, in practice, it has been found that, in order to ensure the production of stable compacts when using this type of bituminous tanning agent, the charged coal must have a moisture content of significantly more than 5 wt%. It is also possible for the pores present in the coal particles to absorb the aqueous bituminous tanning agent or to extract water from the tanning agent so that a substantially uniform distribution of the tanning agent in the material to be treated with the compacted material and thus a uniform wetting of the particle surface by the tanning agent , It can be made unstable as a result of droplet adhesion. This reduces the effect of the emulsion as a binder.

It is an object of the present invention to provide a method for producing compacted products overcoming the problems of this prior art and to provide a method for producing compacted coal particles which is to be dried in advance using a small amount of a water- , Sufficient green strength and high temperature strength.

This object is achieved by a method for producing a compact containing coal particles wherein the coal particles are mixed with a water-containing binder system and the resulting mixture is further treated with a compact by compression,

Prior to mixing with the water-containing binder system,

Characterized in that a portion of the coal particles is subjected to an impregnating step in which the desired material is impregnated.

During impregnation, the material penetrates the pores of the coal particles and fills the pore spaces, thereby preventing the penetration of components of the aqueous binder system, or preventing the penetration of components of the aqueous binder system, And the clogging of the pore neck prevents the components of the aqueous binder system from penetrating into the pores. This avoids the case where the required aqueous binder system on the surface of the coal particles for bonding purposes is no longer able to achieve this bonding purpose after penetration into the pores. Thus, the required amount of aqueous binder system is reduced compared to the way in which the aqueous binder system can penetrate the pores.

Preferably, prior to the impregnation step, at least some of the coal particles or coal particles to be treated with the compact are subjected to a drying process to a water content of less than 8% by weight, preferably to a water content of less than 7% by weight. Particularly preferred is a water content in the range from 4% by weight to less than 8% by weight, particularly preferably in the range from 5% by weight to less than 7% by weight.

Except for water, the aqueous binder system may contain one or more additional components.

The impregnating step may include damping the coal particles into a material, injecting the material into the coal particles, incorporating the material into the movable packed bed of coal particles, or incorporating the material into the fluidized bed of coal particles Lt; / RTI >

The amount of coal particles that are subjected to the impregnation step prior to mixing with the coal particles that do not undergo the impregnation step and with the water-containing binder system may be the same material for the type of coal and the average particle size. According to another variant, some of the coal particles passing through the impregnation step prior to mixing with the water-containing binder system may be of the same coal type as the coal particles not subjected to the impregnation step, but different from the coal particles not subjected to the impregnation step Particle size.

The impregnation of the coal particles to be treated with the compact is not a whole amount but some amount.

According to another variant, a part of the coal particles passing through the impregnation step prior to mixing with the water-containing binder system may be of a different kind of coal than the coal particles not subjected to the impregnation step. In this case, some of the impregnated coal particles and the impregnated coal particles may have the same or different average particle size.

In the case where different amounts are different in that a portion of the coal particles from which the compact is produced corresponds to different coal types and the compacts having different values for low temperature strength or high temperature strength are produced from different types of coal, It is advantageous to impregnate some amount to provide a compact having a less desirable value for the < Desc / Clms Page number 7 >

Although the coal particles from which the compact is produced belong to a single coal class, it may be advantageous to impregnate some amount with the largest average particle size possible if their average particle size is different. Since the specific surface for coal particles having a large average particle size is smaller than the specific surface for coal particles having a small average particle size, the lump of coal particles to be treated with the compacted material is smaller than that in the case of impregnation with small- Lt; RTI ID = 0.0 > impregnated < / RTI >

Although the coal particles from which the compact is produced belong to a single coal class, it may be advantageous to impregnate some amount with the smallest average particle size possible if their average size is different. Since the specific surface for coal particles with a large average particle size is smaller than the specific surface for coal particles with a small average particle size, for a given portion of the mass to be impregnated, the average particle size is greater Many surfaces are impregnated. This has the advantage, for example, that reaction with hot CO ₂ -containing gases occurring over the surface of the coal particles is more widely affected by impregnation since more surface is impregnated.

It is advantageous to impregnate some of this amount if the amount of coal particles produced by the compacted material negatively affects the low temperature strength or the high temperature strength of the compacted material compared to the compacted material produced without such a partial amount. This can reduce the negative impact on the properties of the compact.

Following the implementation of the impregnation step according to the invention of a portion of the coal particles in a quantity, a portion of the impregnated coal particles are combined with the non-impregnated coal particles and the combined coal particles are further treated with the compact.

Bonding of some amount of impregnated coal particles with impregnated coal particles may occur at the bonding step where bonding only and optionally mixing takes place. In this case, an additional step for producing the compact, in particular mixing with the water-containing binder system, is carried out with the product of the coupling. The incorporation of some amount of impregnated coal particles with impregnated coal particles can also occur during mixing with the water-containing binder system.

The material used for impregnation is preferably used as a liquid or by a liquid for impregnation. The liquid refers to a substance that is liquid at a temperature that is dominant during the impregnation step, for example. Impregnation with a liquid, for example, refers to impregnation with a material that is not actually liquid but predominantly emulsified or suspended in the liquid, under the conditions prevailing during the impregnation step.

Compared to the use of solid materials, this improves or even makes possible penetration into the pores or clogging of the pores. To ensure that the material used during the impregnation step remains as a liquid during the impregnation step, the coal particles to be impregnated are preferably heated to a temperature at which the material is liquid.

According to one embodiment, the material in which a portion of the coal particles is impregnated in the impregnation step is water. Thus, in the impregnation step, the water no longer sees any tendency to be sucked into the pores and to absorb the components of the aqueous binder system that are fed to the coal particles after the impregnation step as a result. As a result, in the case of the prior methods, the components sucked into the pores and consequently ineffective in the binding of the compact can contribute to the binding of the compact.

Limiting the proportion of water-impregnated compacts in the fill mixture for the pig iron production process, with a carbon carrier having a lower moisture content than the compact, allows the amount of water introduced into the pig iron production process to be limited to an acceptable amount.

According to another embodiment, the material in which a portion of the coal particles is impregnated in the impregnating step is a water-insoluble and / or water repellent material. If the pores are filled with this type of material in the impregnation step and thus the pore walls are applied with this type of material, the tendency to absorb the components of the aqueous binder system of the pores decreases. If the outlet of the pores on the surface of the coal particles is closed by this type of material, no component of the aqueous binder system can penetrate into the pores. As a result, a component that is previously sucked into the pores and consequently ineffective in the binding of the compact can contribute to the binding of the compact.

The water-insoluble and / or water-repellent material preferably belongs to the group of substances including waxes, organic coke plants or refinery products and plastic or plastic pieces. This may be waste oil. This may be bitumen. These materials are generally available inexpensively in large quantities.

In this case, it is advantageous that the impregnation step is carried out at a temperature at which the water-insoluble and / or water repellent substance is a liquid, in particular a viscous liquid. In this regard, the liquid is considered viscous when the viscosity is at least 1 Pas and at most 100 Pas, for example 10 Pas. Under these conditions, the material diffuses on the surface of the coal particles and penetrates into the outlet of the pores, but hardly penetrates into the interior of the pores. This keeps the consumption of water-insoluble and / or water-repellent materials low during the impregnation step. Advantageously, the water-insoluble and / or water repellent material solidifies at the outlet of the pores on the surface of the coal particles upon cooling.

According to another embodiment, the substance in which a portion of the coal particles is impregnated in the impregnation step is an aqueous solution of the desired substance or a mixture of substances. For example, it is molasses which is an aqueous solution of a mixture of carbohydrate and other natural substances. In principle, any type of dissolved material which improves the high temperature strength and low temperature strength of the compact can be used, for example lignin caustic soda or starch from waste liquors depending on the pulp production can be used. It is preferable to use a solution or a mixture of substances which is converted into a water-insoluble substance by heat treatment and / or chemical reaction. As a result, the effects caused by these substances or mixtures of substances are not reduced by being dissolved in the water of the water-containing binder system and being washed away from the pores.

According to another embodiment, the substance in which a portion of the coal particles is impregnated in the impregnation step is an aqueous suspension of solid colloid, the solid material having water repellency. Examples include suspensions of wax, colloidal talc or graphite in water. If a solid material is deposited on the pore or pore neck, due to the high surface tension of the water repellent solid material, it becomes more difficult for the water-containing binder system to enter.

According to a further embodiment, the substance in which a part of the coal particles is impregnated in the impregnation step is, on the one hand, an emulsion containing water and on the other hand a crude tar obtained from bitumen, , Wax, or oil. When this type of emulsion penetrates the pores, the carbon-containing material is deposited as a thin layer on the pore surface. During pyrolysis, a carbon layer is produced from these thin layers. They reduce the reactivity of the compact to a hot CO ₂ -containing gas compared to the embodiment where a thin layer of material is not deposited at all in the pores. This type of effect also occurs when some amount of coal particles are not emulsified in the impregnation step, for example, the material is bitumen. The occurrence of this type of effect is due to the fact that the carbon layer produced from the material contains little or no material that reacts catalytically to the reaction with the hot CO ₂ -containing gas. On the contrary, the material to be treated with coal particles or compacts contains a component which acts as a catalytic reaction, for example iron or alkali. Thus, the reactivity of the compacts whose surfaces and pores are covered with the carbon layer produced from the material is lower than that of the compacts without this type of carbon layer.

When using coal particles that require pre-drying before being treated with the compact, for commercial reasons it is advantageous not to pursue drying with a water content of less than 5% by weight, i.e. a water content of at most 4% by weight. As a result, the production of additional pore volume as a result of drying is limited, so that less material is absorbed in the impregnation step. Correspondingly, less material is used in the impregnation step. In addition, the expenditure required for drying in terms of equipment and energy is less.

The lower limit of the amount of the material known as the impregnating agent to be added in the impregnation step is 0.3% by weight, preferably 0.5% by weight, based on the weight of the impregnated part of the material to be treated with the compact, By weight, particularly preferably 1% by weight, and the upper limit is 5% by weight, preferably 3% by weight, particularly preferably 2% by weight. Adding more than 5% by weight of the impregnant is economically undesirable. When less than 0.3% by weight of the impregnant is added, impregnation is no longer effective.

According to one embodiment of the process according to the invention, the binder system contains molasses and quicklime or hydrated lime. The binder system may also be composed of these components. According to a further embodiment, the binder system contains molasses in combination with strong inorganic acids such as, for example, phosphoric acid, sulfuric acid or nitric acid.

According to one embodiment of the process according to the invention, the binder system contains an oil-in-water emulsion. The binder system may be composed of this type of emulsion.

According to a further embodiment, the binder system contains products from pulp production waste water, starch, cellulose, sugar beet chips, pulp pulp, wood pulp or long chain polymer electrolytes such as, for example, carboxymethylcellulose.

Binder systems containing quicklime or hydrated lime have the disadvantage that quicklime (CaO) and hydrated lime (Ca (OH) ₂ ) increase the reactivity of the compact to a hot CO ₂ -containing gas as a result of the catalytic effect, The embodiment without the gypsum or hydrated lime has the advantage of providing relatively low reactivity to the compact.

According to one embodiment of the process according to the invention, the iron-containing particles or the iron oxide-containing particles are also compressed into a compact in a mixture with the coal particles.

According to a particular refinement of the process according to the invention, the compact is subjected to a heat treatment after the compression process. The heat treatment takes place at a higher temperature than the compression process. Heat treatment causes drying and / or curing of the compact. The heat treatment may preferably be effected at a temperature of > = 250 [deg.] C and < = 350 [deg.] C at which the irreversible chemical treatment can modify the binder component. For example, the aqueous binder component may be modified into a water-insoluble component.

The composite produced by this modification can contribute to the strength of the compact. In the case of a binder system containing molasses, for example, the molasses is deformed by caramelization.

According to a particular refinement of the process according to the invention, at least some of the amount of coal particles that have undergone the impregnation step are subjected to a heat treatment prior to mixing with the water-containing binder system after the impregnation step.

The heat treatment may be carried out by subjecting the impregnated portion to a heat treatment separately and bonding it to the impregnated coal particles after the heat treatment, or the impregnated portion may be combined with the impregnated coal particles prior to the heat treatment of the coal particles. Heat treatment causes drying. If there are solutions or emulsions in the pores, the heat treatment may also result in concentration of the solution, suspension or emulsion, thereby causing the pore walls to be coated with dissolved, suspended or emulsified components. In addition to the subsequently added aqueous binder systems, they can contribute to the high temperature strength and low temperature strength of the compact. In addition, the heat treatment can lead to deformation of the coating of the pore wall initially formed as a result of the heat treatment into a water-insoluble component or to a component that lowers the reactivity of the coal particles to a high temperature CO ₂ -containing gas. The maximum temperature of the heat treatment is limited by pyrolysis of the coal particles and is 350 ° C. The lower limit for the temperature during this heat treatment is 150 占 폚.

If the same water-containing emulsion used as the water-containing binder system is used for impregnation, the amount added in the impregnation step is less than the amount of the water-containing binder system added in the subsequent mixing. For example, when using a bituminous bituminous bitumen as a binder system and in an impregnation step, 2-3 wt% is added at the impregnation step, although 7-10 wt% is added later as a binder system. The same applies to the case where the same aqueous solution is used as the water-containing binder system and the same aqueous solution of the substance or mixture of substances is used for impregnation. For example, as a binder system, and when molasses is used in the impregnation step, 3 to 5 wt% is added in the impregnation step, although 6 to 8 wt% is later added as a binder system.

In such a case, a limitation of a specific range is also included. In these cases, a heat treatment is required after the addition in the impregnation step, in order to remove the impregnated liquid or water, so that the emulsified substance or dissolved substance is fixed to the pores or pores. As a result, the pores become clogged or the pores become clogged. Thus, in order to produce the compacts, a lower amount of water-containing binder system is required in the case of production that does not undergo a substantial impregnation step.

Following mixing with a water-containing binder system, treatment with a compressed material can be carried out, for example, by treating the coal particles with a known method or water-containing binder system as disclosed in WO 02 / 50219A1 or AT005765U1, Can be carried out by any suitable method suitable for production.

According to the invention, the addition of a water-containing binder system which is carried out only after the impregnation step of a part of the coal particles by the water-insoluble and / or water-repellent material during the production of the compressed material is carried out, for example, according to WO02 / 50219A1 Thereby reducing the cost of the method compared to the conventional method. On the one hand, the prevention of water absorption by coal during the production of compacts in the water-containing binder system reduces the coal consumption rate in the production process of pig iron in which coke obtained from compacted or compacted materials is used, Because a positive amount of water is present in the compact and thus a smaller amount of energy is consumed to evaporate the water. On the other hand, when the process according to the invention is used, it is possible to eliminate the need for after-drying of the compacts to be carried out in a conventional manner for the production of compacts due to water absorption from the binder system , Or it is possible to save energy by reducing the degree of drying. This makes it possible to omit the installation or operation of the device for post-drying, or to reduce the effort involved in operating the device and the dimensions of the device, I will.

Depending on the type of material used in the impregnation, the reduction of the CO ₂ reactivity of the coke obtained from the semi-coke or the compact produced after pyrolysis of the compact in a melter-gasifier can be obtained as an additional advantageous effort. The coke in the fixed layer of the refinery coke or blast furnace at the fixed bed of the melter-gasifier maintains a stable state from the charge on the bed surface for the achievement of the direct gasification zone in the region of the oxygen nozzle or nozzle, And a low CO ₂ response during operation of the melter-gasifier is desirable to promote the permeability of the fixed bed to the molten phase drainage. The reduction in the CO ₂ reactivity of the refractory coke or coke is caused by the internal surface of the pores of the coal particles in the compact resulting from a portion of the impregnated coal particles which can not be further applied by impregnation with the binder containing the promoter . For example, the binder molasses contains an alkali as a reactivity-promoting substance. If the application of the inner surface of the pores by molasses is prevented, for example, by impregnation with bitumen or wax-containing materials, the CO ₂ reactivity relative to the refined coke or coke obtained by the process without the impregnation step Lower.

In order to improve the permeability of the fixed bed, a lower proportion of small cokes may be added to the coal in the COREX or FINEX method for producing pig iron in the fixed bed of a melter-gasifier. When using the coke produced from the compacts or compacts produced according to the invention, the softening of the refractory coke or coke particles is inhibited by the high temperature of CO ₂ , thereby stopping the decomposition of the particles. That is, the compacts produced according to the present invention are known to improve the thermomechanical stability of the semi-coke compared to compacts produced in a conventional manner. Thus, the thermomechanical stability relates to the aspect of high temperature strength which affects the strength of the refractory coke or coke particles remaining after pyrolysis of the compact in the hot zone. Thermomechanical stability relates to an experimental method in which a compact is exposed to a thermal shock procedure and the resulting coke obtained thereby undergoes a tumbling process. The improved thermomechanical stability is evident by the fact that due to the impregnation according to the present invention, the proportion of large sized materials in the tumbled coke is increased compared to compresses produced in the conventional manner.

The filled stationary layer of the compacts produced according to the invention from the recycled coke obtained by pyrolysis can make the gas permeability and drainage behavior of the stationary layer much better than according to the state of the art. Thus, improvements in the reactivity of the reflective coke can reduce or even prevent the addition of coke to Corlex® or FINEX®-filled coal.

In the coke plant technology field, it is known that increasing the bulk density of the charged coal improves the quality of the coke produced therefrom. The use of large quantities of filled coal to produce metallurgical coke is possible by first compacting the coal to be charged. Thus, in addition to filling the coke facility, method variations on the coke facility in loose fill operations have been developed to provide briquetting or partial mono-lighting of the charged coal. However, in view of the present, there is a problem due to commercial reasons for the production of a single-phase with a bituminous binder, and the production of high-temperature mono-or mono-light from a wonder tar is problematic for health reasons, Is problematic due to the introduction of an undesirable substance into the coke oven.

The process according to the invention for the production of compacts makes it possible to reduce binder consumption or to mitigate the deleterious effects of the reaction-promoting binder component, even when producing compressed coke from a filling material.

The compact may be, for example, a compacted strip or a compacted mold according to compacting.

The compact has a lower limit of 0.5 wt%, preferably 1 wt%, based on the weight of the coal particles to be treated with the compact and the components of the binder system of up to 97 wt% of coal particles and up to 15 wt% of the binder system, By weight and an upper limit of 5% by weight, preferably 3% by weight, particularly preferably 2% by weight, or a water-repellent solid material.

Here, it is understood that 15 wt% of the binder system component means that the binder system component does not contain water, so 15 wt% is related to the binder system non-aqueous component.

According to one embodiment, the compact also contains iron- or iron oxide-containing particles. These types of particles can originate, for example, from dust or slurry that occurs during the production of pig iron or steel.

Hereinafter, a method according to the present invention will be described with reference to the block diagrams shown in Figs.
Figure 1 shows a conventional method for producing a compact without the impregnation step.
2 shows a method according to the present invention for producing a compact through an impregnation step, in which two types of coal are used.
3 shows a method according to the present invention for producing a compact through an impregnation step, in which only one kind of coal is used.

Table 1 shows the evaluation of experiments on the production of compacts in relation to drop strength (SS) and point compressive strength (PCS) of the compact, in the context of a series of experiments. To this end, the compacts according to the process according to the invention were produced by impregnation with some amount of coal particles.

Compounds according to the prior art produced all of the coal particles in water by impregnation with the addition of 3% by weight of water over a period of 1 minute. The compact was a briquette.

The same filling material is used in each case under the same conditions as the green pressed article and the compact produced according to the present invention, the green compact and the compact produced according to the prior art and the molten mass 12% - were the same for both green compacts and for air dried and heat dried compacts.

The water - containing binder system used was a system consisting of molasses and quicklime. The molasses itself had a water content of 20 mass%. The following molasses available for purchase was used in the binder system: sugarcane molasses from Tate & Lyle, having a total sugar content of 51%. Binder type quicklime was powdered quicklime from Walhalla Kalk. For impregnation, bitumen was used as impregnation agent. The bitumen used was Mexphalte 55 from Shell.

The impregnating bitumen was mixed in an FM130D plow-blend mixer from Loedige; Other mixtures were produced in a R08 W batch mixer from Eirich.

The stirrer from the Koeppern yarn used in the stirring process consisted of a vertical cylindrical vessel in which a central rotating shaft with a stirrer blade was guided.

Green compacts were produced by Type 52/10 laboratory roller presses from Pleasant Crafts. The format of the cushion shape selected for the green compact was nominal volume 20 cm ³ . The material to be compressed was filled with a gravity feeder. Experimental roller presses were used to produce strips containing a plurality of green compacts. These strips contained green compacts in both the edge area of the strip and the center area of the strip. To obtain each green compact or each compact for determination of drop strength or point compressive strength, the strip is peeled along the line between the respective green compacts. In principle, the strips were split into individual green compacts upon discharge from the test roller presses.

Following the stirring process in the stirrer, to produce a green compact, the stirred mixture as the material to be compacted was subjected to compression in a laboratory roller press. The green compact thus obtained was still ductile as expressed in technical terms by the prefix " Green ", and undergoes a curing process to obtain a compacted article. This curing process can be done, for example, by at least partially drying by storage and / or heat treatment in air.

After the compression process, each of the green compacts in which the technical term Green was used was immediately tested for drop strength (SS) and point compressive strength (PCS). The results of these experiments are indicated in the " immediate " column for PCS and SS. Drop strength and point compressive strength were measured after 1 hour curing in air and after 24 hours curing in air, respectively. The results of these experiments are indicated in the columns "1 hour" and "24 hours".

In a drop-and-sature experiment (see ASTM D440) to determine the drop strength, 2 kg of green compacts or compacts weighed by air drying or heat drying were weighed through a vertical pipe at a height of 5 m, And dropped four times into a collection receptacle having a base formed into a plate. The vertical pipe had a diameter of 200 mm, and the collection receptacle had a diameter of 260 mm. The steel plate was 12 mm thick. The evaluation of the drop-satellite experiment by screen analysis was made after the second and fourth fall. The numerical values for the drop strength (SS) in Table 1 represent the ratio of the particle size portion, which is > 20 mm after each of the four drops.

The point compressive strength was determined by a Type 469 test machine from ERICHSEN. During this experimental procedure, each green compact or compact, which is cured by air drying or thermal drying, is applied to a lower platen coupled to a force transducer and a spindle for applying a creeping swelling pressure load And held between upper platens that are continuously loaded by the drive. The lower plate was formed from a round plate having a diameter of 80 mm, and the upper plate was formed into a horizontal round bar having a diameter of 10 mm. The forward speed for the upper platen was 8 mm / min. The point compressive strength (PCS) was recorded as the maximum load-bearing performance of the green or cured compact prior to rupture, and Table 1 shows the average point compressive strength in rupture in Newtons. In each case, six green compacts or compacts from the edge area of the strip produced in the lab roller presses and six green compacts or compacts from the center area were tested. The mean values of the data produced in these experiments were calculated and the minimum and maximum values were ignored in each case. The average values are listed in Table 1.

Experiment number PCS [N]
Immediately PCS [N]
1 hours PCS [N]
24 hours SS
Immediately SS
1 hours One 46 84 149 70 78 2 104 166 252 73 67

In Experiment 1, according to the prior art, 70% by weight of an enamel with an average particle size (d50) of 0.95 mm with 30% by weight of Blackwater coal having an average particle size (d50) of 0.8 to 1.0 mm (Ensham) coal was used as the coal particles to be treated with the compact.

Blackwater coal is from BHP Billiton, Queensland, Australia.

EnSam Coal is from Ensham Resources, Queensland, Australia.

This material to be treated with the compact was treated with the compact as shown in the lower part of Fig. 1 for coal 1. Molasses in the water-containing binder system was used in an amount of 12% by weight, based on the weight of the material to be treated with the compact. The molasses used itself had a water content of 20% by weight. In addition to molasses, the water-containing binder system also contains 2.5 wt% of quicklime based on the weight of the material to be treated with the compact. The point compressive strength and the drop strength at different times are described in the first data column of Table 1.

In Experiment 2, according to the present invention, the same material to be treated with the compact was used. However, the enamel coal used was impregnated with bitumen. The bitumen used was cell-specific bitumen A with a softening point of 85 ° C. The amount of bitumen used was 2.1% by weight based on the weight of the material to be treated with the compact or 3% by weight based on the enamel coal to be impregnated. The temperature of the pre-mixed coal to bitumen was 108 ° C. After impregnation, impregnated enam coal was combined with black water coal. After bonding, the molasses in the water-containing binder system was treated in a similar manner to Experiment 1, except that the molasses in the water-containing binder system was used in an amount of 8 wt% based on the weight of the material to be treated with the compact. The molasses used itself had a water content of 20% by weight. In addition to molasses, the water-containing binder system was also composed of 2% by weight of quicklime, based on the weight of the material to be treated with the compact. In each case, after addition of quicklime, 2% additional water was added based on the weight of the coal material to be treated with the compact to supply the quicklime with the necessary moisture for the reaction.

Although the drop strength is similar to the drop strength of the compact produced according to the prior art, it can be appreciated that the compact produced according to the present invention has a higher point compressive strength than the compact produced according to the prior art.

In addition, a portion of the coal particles to be impregnated may undergo more than one impregnation step.

According to figure 1, the coal to be treated with the compact, in this case the briquetted coal, is subjected to a drying step (2) and then to the particle size required by the grain refining (3). Subsequently, during the mixing (5) in which the water-borne binder system (4), in this case molasses, is added to the coal particles thus obtained and, optionally, can be carried out in one or more stages, a solid such as hydrated lime or quicklime A particulate binder component is added. The thus obtained mixture is subjected to a stirring step (6) and a compression step (7). The product 9 obtained after the curing process 8 is molded.

The method according to the invention as shown in Figure 2 takes the impregnation step 10 in which a quantity A of the coal particles 12 used to produce the compact is impregnated with the material 11, Which is different from the method shown in Fig. After the impregnation step 10, the mixing process of the water-containing binder system 4 and the part B of the coal particles 13 used to produce the compacts and the further treatment of the resulting mixture, As shown in Fig. Thus, the coal particles used to produce the compact contain both some amount (A) 12 and some amount (B) 13. Some amounts (A) 12 and some (B) 13 belong to different coal types.

Unlike the case of Fig. 2, the partial amount (A) 12 and the partial amount (B) 13 of the coal particles used for producing the compact in Fig. 3 belong to the same coal type. The coal 1 to be treated is subjected to a drying step (2) and then to the particle size required by grain refining (3). The coal particles thus obtained are subjected to an inspection step (14). As part of the amount (A) of the coal particles (12) used to produce the compact, the coarse grain fraction obtained thereby is subjected to an impregnation step (10) in which the material (11) is impregnated with an impregnation agent. After this impregnation step 10, a mixing step (5) of the moisture-containing binder system (4) and a part of the coal particles (13) used to produce the compact (5) Is executed in a manner corresponding to Fig. Some amount B of the coal particles 13 used to produce the compact is the fraction of fine particles obtained during the inspection process 14.

After the impregnation step 10, the heat treatment 12 may be carried out prior to mixing with the water-containing binder system 4. [

Generally, during the production of the compact according to the invention, the addition of water-borne binder molasses / quicklime to the material to be treated with the compact can be carried out such that molasses and quicklime are added simultaneously or quicklime and molasses are added in succession have.

Here, in the case of the use of the impregnated bitumen, it is preferred that a first part of the molasses for the purpose of producing the compact is added and then the quicklime is added after mixing. After the mixture thus obtained is kept as it is, the remaining amount of molasses for the purpose of producing a compact is added. The above amounts and amounts together provide molasses for the production of compacts. The advantage of this procedure is that during mixing of the water-containing binder system and the material to be treated with the compact, agitation of the quicklime in the soft impregnant is prevented or reduced.

The addition of molasses, which itself contains water prior to the addition of quicklime, also allows the quicklime to use the moisture from the molasses for its reaction. A maximum of half, preferably one-third, of molasses can be added prior to quicklime.

1: Coal
2: Drying process
3: Granulation
4: Water-containing binder system
5: Mixing process
6: stirring step
7: Compression process
8: Curing process
9: Products
10: impregnation step
11: Substance (impregnating agent)
12: Partial amount (A) of coal particles for producing compacted material
13: Partial amount of coal particles to produce compact (B)
14: Inspection process
Patent literature
WO02 / 50219A1
WO9901583A1
AT005765U1

Claims (17)

A method for producing a compact containing coal particles, wherein the coal particles are mixed with a water-containing binder system and the resulting mixture is further processed into a compact by compression,
Prior to mixing with the water-containing binder system, a portion of the coal particles undergoes an impregnating impregnation step with the predetermined amount of the predetermined amount,
The lower limit of the amount of the substance to be added in the impregnation step is 0.3% by weight based on the weight of the coal particles to be treated with the compact,
Characterized in that the material prevents the components of the water-containing binder system from penetrating into the pores of the coal particles
Way.
The method according to claim 1,
The impregnating step may include damping the coal particles with the material, spraying the material onto the coal particles, incorporating the material into the movable packed bed of coal particles, And < RTI ID = 0.0 >
Way.
3. The method according to claim 1 or 2,
Wherein the material impregnated with the coal particles in the impregnating step is water
Way.
3. The method according to claim 1 or 2,
Wherein the material impregnated with the coal particles in the impregnation step is a water-insoluble and / or water-repellent material
Way.
3. The method according to claim 1 or 2,
Wherein the material impregnated with the coal particles in the impregnation step is an aqueous solution of a predetermined substance or a mixture of substances
Way.
3. The method according to claim 1 or 2,
Wherein the material impregnated with the coal particles in the impregnating step is an aqueous suspension of solid colloid, the solid material being water repellent
Way.
3. The method according to claim 1 or 2,
Characterized in that the substance to be impregnated with the coal particles in the impregnation step is an emulsion containing water on the one hand and a carbon-containing substance on the other hand
Way.
3. The method according to claim 1 or 2,
The upper limit of the amount of the substance to be added in the impregnation step is 5 wt% based on the weight of the coal particles to be treated with the compact
Way.
3. The method according to claim 1 or 2,
Characterized in that the binder system comprises molasses and quicklime or hydrated lime
Way.
3. The method according to claim 1 or 2,
Characterized in that the binder system contains an oil-in-water emulsion
Way.
3. The method according to claim 1 or 2,
Iron-containing particles or iron oxide-containing particles are also treated with a mixture with said coal particles
Way.
3. The method according to claim 1 or 2,
Characterized in that the compact is subjected to a heat treatment after the compression process
Way.
3. The method according to claim 1 or 2,
Wherein at least a part of the coal particles subjected to the impregnation step is subjected to a heat treatment before mixing with the water-containing binder system after the impregnation step
Way.
A compact produced by the process of claim 1, containing up to 97% by weight of coal particles and up to 15% by weight of a binder system component,
Characterized in that it contains a water-insoluble and / or water-repellent substance, or a water-repellent solid substance in an amount of 0.3 wt% of the lower limit and 5 wt% of the upper limit, based on the weight of the coal particles treated with the compact doing
Compressed.
15. The method of claim 14,
Characterized in that said water-insoluble and / or water-repellent material belongs to the group of substances consisting of wax, organic coke plant or refinery products and plastic or plastic pieces and waste oil
Compressed.
16. The method according to claim 14 or 15,
Characterized in that the compact also contains iron-containing particles or iron oxide-containing particles
Compressed.
16. The method according to claim 14 or 15,
Which is used as a carbon carrier in a process for producing pig iron in a fixed bed or for producing a process carbon carrier for producing pig iron in a fixed bed,
Compressed.

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