Method for producing molded coke by utilizing coke powder as resource

Abstract

The present application provides a method for producing molded coke by utilizing coke powder as a resource, comprising the following steps: 1) mixing coke powder with water to obtain wet coke powder. 2) mixing wet coke powder with a binder to obtain a mixing and stirring step of a batch material. 3) transferring the batch material to a buffer bin, and outputting the batch material quantitatively to a briquette machine through the buffer bin. 4) pressurizing the batch material through a briquette machine to obtain a cold pressing step of wet molded coke. 5) drying the wet molded coke through a dryer to obtain a drying step of molded coke. The drying step comprises: desulfurizing and denitrifying the flue gas of the coke oven to obtain flue gas to be dried, passing the flue gas to be dried into a dryer, drying the wet molded coke to obtain dried flue gas and molded coke, and removing dust from the dried flue gas and discharging it. The present application realizes the production of molded coke by utilizing coke powder as a resource, and improves the mechanical strength of the molded coke.

Description

Technical Field

[0001] The present application relates to the technical field of coal forming, and in particular to a method for producing formed coke by utilizing coke powder as a resource. Background Art

[0002] As a by-product of the coke production process, the utilization value of coke powder has not been fully developed for a long time. A large amount of coke powder is used as a low-value fuel, resulting in a huge waste of resources. As a bulk material, coke powder will generate a large amount of dust during production, transportation and storage, causing great pollution to the environment. In order to solve dust pollution and meet environmental protection requirements, enterprises need to configure a large number of dust removal or dust suppression facilities, which greatly increases the production costs of enterprises. Enterprises urgently need to find more efficient and environmentally friendly ways to utilize coke powder to fully tap its value, reduce resource waste, reduce negative impacts on the environment, and improve the economic benefits of enterprises.

[0003] Ferroalloys are mainly used to produce ferrosilicon, ferromanganese, ferrochrome and other ferroalloy products. In the ferroalloy production process, coke is the main reducing agent and heat source, and its quality and quantity have an important impact on the quality and output of the product. With the continuous development of the ferroalloy industry, the demand for coke is also increasing year by year. With the continuous development of technology, the demand for coke by these enterprises is also increasing year by year. Therefore, coke powder is gradually used to produce coke instead of coke.

[0004] At present, in the process of producing molded coke, coke powder is mixed with a binder, then heated to soften and shape it, and then carbonized or sintered to produce molded coke. Not only is the process complicated, but it also consumes a lot of heat source, resulting in a high production cost of molded coke. Summary of the invention

[0005] The present application provides a method for producing molded coke by resource utilization of coke powder, so as to solve the above-mentioned problems mentioned in the background technology.

[0006] The present application provides a method for producing molded coke by utilizing coke powder as a resource, comprising the following steps:

[0007] 1) Mixing coke powder with water to obtain wet coke powder.

[0008] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0009] 3) The batch material is transported to the buffer bin, and the batch material is quantitatively output to the buffer output step of the ball press through the buffer bin.

[0010] 4) The batch material is pressurized by a briquette machine to obtain the cold pressing molding step of wet coke.

[0011] 5) Drying the wet coke in a dryer to obtain the coke.

[0012] The drying step includes: desulfurizing and denitrifying the coke oven flue gas to obtain the flue gas to be dried, passing the flue gas to be dried into a dryer, drying the wet coke to obtain drying flue gas and coke, and removing dust from the drying flue gas and discharging it.

[0013] Optionally, the particle size of the coke powder is ≤5 mm.

[0014] Optionally, the amount of water added is 11-20% of the weight of the batch material, and the amount of the binder added is 4-8% of the weight of the batch material.

[0015] Optionally, the binder includes the following components in parts by weight:

[0016] 40-50 parts by weight of bentonite, 30-35 parts by weight of starch, 10-20 parts by weight of lignin, 5-10 parts by weight of sodium humate, 5-7 parts by weight of sodium carboxymethyl starch, 1-3 parts by weight of straw powder, 0.5-1 parts by weight of quicklime, 0.5-1 parts by weight of sodium 2-naphthyloxyacetate and 0.2-0.4 parts by weight of didodecyl thiodipropionate.

[0017] Optionally, the starch is one or more of corn starch, potato starch, and tapioca starch.

[0018] Optionally, the moisture content of the binder is ≤0.2%.

[0019] Optionally, the temperature of the flue gas to be dried is 180-190°C.

[0020] Optionally, during the cold pressing step, the pressure of the ball press is 30-40MPa.

[0021] Optionally, in the drying step, the moisture content of the obtained coke is less than 0.5%.

[0022] Optionally, the method for producing formed coke further comprises a material returning step, and the material returning step comprises:

[0023] A bar screen is fixed at the discharge port of the ball press to transport the screened material to the buffer bin.

[0024] A bar screen is fixed at the dryer discharge port to transfer the screened material to the buffer bin. And,

[0025] The drying flue gas obtained in the drying step is subjected to water bath dust removal to obtain clean gas and dust-removed precipitate, the clean gas is discharged, and the dust-removed precipitate is mixed with coke powder as a raw material.

[0026] The method for producing molded coke by utilizing coke powder as a resource provided in the present application realizes the production of molded coke by utilizing coke powder as a resource, and has the following beneficial effects compared with the prior art:

[0027] (1) Before mixing the coke powder with the binder, the coke powder is first mixed with the binder to form wet coke powder, thereby avoiding the escape of coke powder, making the operating environment cleaner, and being beneficial to the personal safety of the operators. At the same time, the waste caused by the escape of coke powder is avoided. The wet coke powder is then mixed with the binder to obtain a batch material. The coke powder and the binder are in close contact, so that the coke powder particles are bonded together by the binder to form a tighter structure, thereby enabling the molded coke to have a higher strength. The mixed batch material is temporarily stored in a buffer bin, and the batch material is quantitatively transported to a briquette machine for pressing and molding. Wet molded coke is obtained at the discharge port of the briquette machine. Finally, the waste coke oven flue gas is used as a drying heat source to dry the wet molded coke in the dryer to obtain a molded coke product. The present application does not need heating to melt the binder during pressure molding, and the molded coke is obtained only by drying, and the molded wet coke does not need to be carbonized or sintered, which greatly reduces the heat consumption. Compared with the production of molded coke in the prior art, it not only simplifies the production process, making the process simple and easy to operate, but also reduces the heat consumption of the carbonization process, and uses the discarded coke oven flue gas as the drying heat source, which has a good energy-saving effect.

[0028] (2) The bentonite added to the binder absorbs the water in the wet coke powder and expands to form a three-dimensional network structure, which increases the viscosity of the binder. The starch can improve the adhesion when it meets water, and the long-chain structures between lignin molecules are intertwined, which can form a strong connection between the coke powders. At the same time, quicklime generates alkaline calcium hydroxide when it meets water, which opens the ester bonds in the straw powder and expands the fibers in the straw powder, increasing the affinity between coke powder and straw powder, and between coke powder and coke powder, and synergizes with bentonite to improve the compactness between coke powders, thereby improving the strength of the molded coke. The addition of sodium carboxymethyl starch can generate a colloid with higher viscosity and improve the adhesion between coke powders when it meets water. However, the addition of sodium carboxymethyl starch, due to its high viscosity, easily leads to a low degree of dispersion of the binder in the coke powder. When straw powder is mixed with coke powder, it will not produce high viscosity, and straw powder has a certain particle size, which can increase the friction coefficient between coke powder and bentonite, starch, and sodium carboxymethyl starch in the binder during the mixing process, disperse the viscosity of sodium carboxymethyl starch, and make the binder more easily dispersed in the coke powder while playing a viscous role, which not only improves the structural stability and strength of the molded coke. Sodium 2-naphthyloxyacetate allows the wet coke to maintain internal structural stability and strength during subsequent drying, and didodecyl thiodipropionate can improve the smoothness of the binder when mixed with coke powder.

[0029] (3) This application adopts cold pressing and bonding agent, realizes the most concise process, shortens the production cycle, simplifies the process flow, reduces the production cost, produces the molded coke products that meet the market demand, and solves the high value-added application problem of coke powder. At the same time, the residual heat of the flue gas after the combustion of the coke oven heating gas is used to dry the molded coke, so that the residual heat of the flue gas can be utilized, avoiding the carbon emission generated by the use of combustion heating to dry the molded coke. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A process flow chart of a method for producing molded coke by utilizing coke powder as a resource provided in one embodiment of the present application;

[0032] Figure 2 A process flow chart of a method for producing molded coke by resource utilization of coke powder provided in another embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0034] like Figure 1 As shown, the present application provides a method for producing molded coke by utilizing coke powder as a resource, comprising the following steps:

[0035] 1) Mixing coke powder with water to obtain wet coke powder.

[0036] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0037] 3) The batch material is transported to the buffer bin, and the batch material is quantitatively output to the buffer output step of the ball press through the buffer bin.

[0038] 4) The batch material is pressurized by a briquette machine to obtain the cold pressing molding step of wet coke.

[0039] 5) Drying the wet coke in a dryer to obtain the coke.

[0040] The drying step includes: desulfurizing and denitrifying the coke oven flue gas to obtain the flue gas to be dried, passing the flue gas to be dried into a dryer, drying the wet coke to obtain drying flue gas and coke, and removing dust from the drying flue gas and discharging it.

[0041] Specifically, coke powder, as a by-product in the coke production process, is generally used as a low-value fuel, resulting in a great waste of resources. In addition, coke powder will generate a large amount of dust during production, transportation and storage, causing great pollution to the environment. Therefore, the resource utilization of coke powder is an urgent problem to be solved. The present application mixes coke powder and a binder evenly, and then performs pressure molding to produce molded coke, which not only turns coke powder into treasure, but also allows molded coke to replace a part of coke or coke particles for use in ferroalloys, nonferrous metals, calcium carbide, steel and other industries, thereby solving the high value-added application of coke powder and improving the economic benefits of coking enterprises, and reducing production costs, achieving a good purpose of reducing costs and increasing efficiency. At the same time, in the production process of molded coke, the waste heat of the flue gas after the combustion of the coke oven heating gas is used to dry the molded coke, so that the waste heat of the flue gas can be utilized, avoiding the carbon emissions generated by the use of combustion heating to dry the molded coke.

[0042] The method for producing molded coke by utilizing coke powder as a resource comprises the following steps:

[0043] 1) Mix the coke powder with water to obtain wet coke powder. The beneficial effect of this design is that before mixing the coke powder with the binder, the coke powder is first mixed with water. Since the particle size of the coke powder is small, it is easy to fly, which will cause the powder to escape from the environment and pollute the operating environment. The coke powder is first mixed with water to form wet coke powder, which avoids the escape of coke powder, makes the operating environment cleaner, is beneficial to the personal safety of the operators, and avoids the waste of coke powder. At the same time, adding water makes the coke powder particles initially tight and the volume becomes smaller, which is convenient for subsequent mixing with the binder.

[0044] 2) The wet coke powder and the binder are mixed and stirred to obtain a batch material. The wet coke powder and the binder are mixed and stirred by a wheel mixer. During the mixing process, the particles of the wet coke powder and the binder are rolled to make the particle size of the obtained batch material uniform, which is convenient for subsequent pressure molding. During mixing, under the action of mechanical force, the coke powder and the binder are in close contact, and the binder forms a colloidal or crystal structure on the surface and in the gaps of the coke powder particles, so that the coke powder particles are bonded by the binder to form a tighter structure, thereby enabling the molded coke to have a higher strength.

[0045] 3) The batch material is transported to the buffer bin, and the batch material is quantitatively output to the briquetting machine through the buffer bin. The buffer bin is used to temporarily store the mixed batch material and quantitatively transport the batch material to the briquetting machine for pressing and molding. In this way, the briquetting machine can continuously press the balls through the buffering and transporting function of the buffer bin, thereby realizing the continuous production of molded coke.

[0046] 4) The batch material is pressurized by a briquette machine to obtain the cold pressing step of wet coke. The briquette machine presses the batch material at room temperature without additional heating, which reduces the heat consumption, saves energy consumption, and reduces production costs.

[0047] The room temperature refers to a temperature of 20-30° C. The wet coke obtained at the discharge port of the briquette press is round or cylindrical, and the particle size of the wet coke is determined according to the actual working conditions.

[0048] 5) Drying the wet coke by a dryer to obtain the drying step of the coke. The drying step includes: desulfurizing and denitrifying the flue gas of the coke oven to obtain the flue gas to be dried, passing the flue gas to be dried into the dryer, drying the wet coke to obtain drying flue gas and coke, and removing dust from the drying flue gas and discharging it. The flue gas generated after the combustion of the coke oven heating gas contains a certain amount of heat. If the flue gas is directly discharged, the heat in the flue gas will be wasted, and the wet coke in the dryer needs to be dried by combustion heating, which not only increases the heat loss and the production cost of the enterprise, but also increases the carbon emission generated by combustion, causing pollution to the surrounding environment. In the present application, the flue gas of the coke oven is desulfurized and denitrified to obtain the flue gas to be dried, and is passed into the dryer to provide heat for the drying of the wet coke, which not only achieves the purpose of drying the wet coke, but also makes the waste heat of the flue gas available, thereby reducing the production cost. Among them, the desulfurization and denitrification process is a commonly used method in this field, which will not be described here.

[0049] In the present application, coke powder is mixed with a binder, pressed and formed by a briquette machine, and then dried by a dryer to remove moisture and a small amount of volatile matter to obtain a molded coke product. During the press forming, there is no need to heat to melt the binder, and the molded coke is obtained only by drying, and the molded wet coke does not need to be carbonized or sintered, which greatly reduces the heat consumption. Compared with the production of molded coke in the prior art, it not only simplifies the production process, makes the process simple and easy to operate, but also reduces the heat consumption of the carbonization process, and uses the discarded coke oven flue gas as the drying heat source, which has a good energy-saving effect.

[0050] The present application realizes the resource utilization of coke powder to produce molded coke through the above scheme. Before mixing the coke powder with the binder, the coke powder is first mixed with the binder to form wet coke powder, thereby avoiding the escape of coke powder, making the operating environment cleaner, and facilitating the personal safety of operators. At the same time, it avoids the waste caused by the escape of coke powder. The wet coke powder is then mixed with the binder to obtain a batch material. The coke powder and the binder are in close contact, so that the coke powder particles are bonded by the binder to form a tighter structure, thereby enabling the molded coke to have a higher strength. The mixed batch material is temporarily stored in a buffer bin, and the batch material is quantitatively transported to a ball press for pressing and molding. The wet molded coke is obtained at the discharge port of the ball press. Finally, the discarded coke oven flue gas is used as a drying heat source to dry the wet molded coke in the dryer to obtain a molded coke product. The present application does not need heating to melt the binder during pressure molding, and the molded coke is obtained only by drying, and the molded wet coke does not need to be carbonized or sintered, which greatly reduces the heat consumption. Compared with the production of molded coke in the prior art, it not only simplifies the production process, making the process simple and easy to operate, but also reduces the heat consumption of the carbonization process, and uses the discarded coke oven flue gas as the drying heat source, which has a good energy-saving effect.

[0051] Optionally, the particle size of the coke powder is ≤5 mm.

[0052] Specifically, choosing a suitable particle size of coke powder is beneficial to the forming of molded coke and also beneficial to the molded coke having good mechanical strength. When used in ferroalloys and other fields in the future, the molded coke can maintain a good structure during the combustion process, provide a stable heat source for ferroalloy production, and avoid collapse during the combustion process. If the particle size of coke powder is too large, the contact area between coke powder and binder, and between coke powder and coke powder is reduced, so that the bonding tightness between coke powder particles will be reduced, which will lead to a sparse structure inside the molded coke and reduce the mechanical strength of the molded coke.

[0053] Optionally, the amount of water added is 11-20% of the weight of the batch material, and the amount of the binder added is 4-8% of the weight of the batch material.

[0054] Specifically, the addition of water can not only reduce the escape of coke powder in the environment, but also enable the binder to form a viscous substance when the wet coke powder is mixed with the binder. At the same time, adding an appropriate amount of water can make the binder better infiltrate the coke powder surface, improve adhesion, and the binder after adding water can better penetrate into the coke powder particles, enhance the bonding effect, and thus improve the compactness of the internal structure of the molded coke and improve the mechanical strength of the molded coke. If the amount of water added is too large, the water content of the batch is too high, which makes it difficult to pressurize the batch, and also makes the subsequent drying process longer, extending the production cycle of the molded coke, which is not conducive to the control of production costs. If the amount of water added is too small, the bonding effect of the binder is not fully exerted, resulting in a decrease in the compactness of the internal structure of the molded coke, and thus a decrease in the mechanical strength of the molded coke product.

[0055] The addition of binder makes coke powder closely contact with binder and coke powder with coke powder. The binder forms colloidal or crystal structure on the surface of coke powder particles and in the gaps, so that coke powder particles form a tighter structure through the bonding effect of the binder, thereby making the molded coke have higher strength. Too much binder will increase the ash content of the molded coke during subsequent use. Too little binder will cause the molded coke to fail to reach the target mechanical strength. When the molded coke is used to replace coke in ferroalloy production, it will collapse due to insufficient mechanical strength, and cannot maintain a good combustion skeleton, and thus cannot provide a continuous and stable heat source.

[0056] Optionally, the binder includes the following components in parts by weight:

[0057] 40-50 parts by weight of bentonite, 30-35 parts by weight of starch, 10-20 parts by weight of lignin, 5-10 parts by weight of sodium humate, 5-7 parts by weight of sodium carboxymethyl starch, 1-3 parts by weight of straw powder, 0.5-1 parts by weight of quicklime, 0.5-1 parts by weight of sodium 2-naphthyloxyacetate and 0.2-0.4 parts by weight of didodecyl thiodipropionate.

[0058] Specifically, bentonite is a natural clay mineral with a large number of layered structures and fine pores. When the binder is mixed with wet coke powder, the bentonite absorbs the moisture in the wet coke powder and expands to form a three-dimensional network structure, which increases the viscosity of the binder. At the same time, under the stirring action, the bentonite is dispersed in the gaps between the coke powder particles, bonding the coke powder particles together, and providing cohesion for the internal structure of the molded coke. In the process of mixing the binder with wet coke powder, the starch can improve the adhesion when it meets water, and then improve the adhesion between the coke powder particles, so that the coke powder particles can be in close contact with each other, thereby improving the compactness of the internal structure of the molded coke and improving the mechanical strength of the molded coke. Sodium humate contains abundant active groups such as carboxyl, phenolic hydroxyl, hydroxyl and amino groups, has good adsorption and permeability, forms physical and chemical crosslinks between coke powder particles, thereby achieving adhesion and enhancing the structural strength of the molded coke. The anionic groups on the molecular chain of sodium carboxymethyl starch easily form hydrogen bonds with water, and produce larger colloids after meeting water, which makes the added points have a higher viscosity and has a promoting effect on the structural strength of the molded coke.

[0059] The addition of straw powder and quicklime reacts with wet coke powder during mixing, further improving the structural strength of the molded coke. Wet coke powder contains water. During the stirring process, straw powder and quicklime are gradually and evenly dispersed in the coke powder. Quicklime generates calcium hydroxide when it meets water, and releases heat at the same time. Calcium hydroxide becomes alkaline. During the mixing process, straw powder reacts with calcium hydroxide in an alkaline environment. Some organic matter in the straw powder reacts with the alkali to open the ester bond therein and expand the fiber in the straw powder, increasing the affinity between coke powder and straw powder, and between coke powder and coke powder. It also works synergistically with bentonite to improve the compactness between coke powders, thereby improving the strength of molded coke. At the same time, although the addition of sodium carboxymethyl starch can generate a colloid with greater viscosity and improve the adhesion between coke powders after meeting water, it is easy to cause the dispersion degree of the binder in the coke powder to be low due to its high viscosity, which prolongs the stirring and mixing time. The addition of straw powder just solves the problem of low dispersion degree. When the straw powder is mixed with the coke powder, the straw powder has a certain particle size, which can improve the friction coefficient between the coke powder and the bentonite, starch, and sodium carboxymethyl starch in the binder during the mixing process, disperse the viscosity of sodium carboxymethyl starch, and make the binder more easily dispersed in the coke powder while playing a viscous role, which not only improves the structural stability and structural strength of the molded coke, but also shortens the stirring time, reduces the energy consumption of the stirring device, and is conducive to reducing costs, saving energy and reducing emissions. At the same time, quicklime releases heat while generating calcium hydroxide when it meets water, which is conducive to the bonding effect of the active groups in each component of the binder on the coke powder, and has a good promoting effect on improving the bonding performance of the binder and the internal structural strength of the molded coke. By adding straw powder and quicklime, and generating alkaline calcium hydroxide during the stirring process, the performance of the binder is improved, making the process simple and easy to operate. If the straw is first soaked in alkali solution, and then the straw is dried and crushed and mixed with coke powder, it will not only lead to a cumbersome process and labor-intensive, but also cause more alkali solution, generate sewage, increase the load of sewage treatment, and cannot release heat during the mixing process, reducing the bonding effect of the binder. At the same time, straw powder can also provide a certain carbon content for the coke and improve the combustion efficiency of the coke. However, the addition amount of straw powder and quicklime needs to be kept within a reasonable range. Excessive addition of straw powder will lead to an increase in the ash content in the coke, which is not conducive to the later combustion of the coke.

[0060] Sodium 2-naphthoxyacetate and didodecyl thiodipropionate are also added to the binder. Sodium 2-naphthoxyacetate contains benzene rings and carboxyl groups. The macromolecular π bonds of the benzene rings can improve the stability of the binder, so that the wet coke maintains internal structural stability and strength during subsequent drying. It contains long-chain alkyl groups, which can improve the smoothness of the binder when mixed with coke powder, and work together with straw powder to improve the mixing uniformity of the binder and coke powder, which helps the coke powder and the binder to fully contact each other, and helps the binder to bind the coke powder particles, thereby improving the structural strength and stability of the coke product. At the same time, didodecyl thiodipropionate has a certain hydrophobicity, which is conducive to the evaporation of water in the wet coke in the subsequent drying step.

[0061] Among them, straw powder is obtained by drying the straw to a moisture content of ≤0.2%, and then crushing the straw into particles with a particle size of 3-10 mm through a crusher. The appropriate particle size is conducive to the coordination between the straw powder and other components in the binder and the coke powder, and avoids the straw powder particles being too large or too small to affect the structural strength of the coke.

[0062] Optionally, the starch is one or more of corn starch, potato starch, and tapioca starch.

[0063] Specifically, starch is used as one of the main components of the binder. The raw materials are easily available and low in cost. It not only achieves the bonding effect of coke powder, but also can reduce the investment cost of the enterprise.

[0064] Optionally, the moisture content of the binder is ≤0.2%.

[0065] Specifically, the binder contains quicklime, which has a high water content and easily causes the quicklime to react with water to generate calcium hydroxide in advance, rather than generating alkaline calcium hydroxide when the coke powder and the binder are mixed and stirred, making it difficult to promote the adhesiveness of the binder to the coke powder during the stirring process.

[0066] Optionally, the temperature of the flue gas to be dried is 180-190°C.

[0067] Specifically, the flue gas to be dried comes from the flue of the coke oven, replacing the heating equipment to provide drying heat for the dryer, achieving the purpose of utilizing the waste heat of the flue gas. The temperature of the flue gas to be dried is 180-190°C, which can not only dry the moisture in the wet coke, but also heat and volatilize the small amount of volatile matter in the wet coke, and will not affect the properties of the coke. And as the water evaporates, the hydroxyl groups in the binder gradually dehydrate and condense with the amino and carboxyl groups to form a spatial network structure, which tightly wraps the coke powder in the network structure, thereby forming a solid with extremely high structural strength.

[0068] Optionally, during the cold pressing step, the pressure of the ball press is 30-40MPa.

[0069] Specifically, the batch is pressed and shaped by the pressure of the briquette machine to obtain wet coke. The addition of the binder improves the adhesion between the coke powder particles and helps the batch to be shaped during cold pressing.

[0070] Optionally, in the drying step, the moisture content of the obtained coke is less than 0.5%.

[0071] Specifically, the moisture content of the coke after drying is less than 0.5%. In this way, the coke contains a small amount of moisture during transportation, which generates a certain force between the internal structures of the coke, which is conducive to maintaining the cohesion inside the coke and enabling the coke to be transported over long distances. At the same time, maintaining an appropriate moisture content is conducive to easy combustion and stable heat release when the coke is used.

[0072] like Figure 2 As shown, optionally, the method for producing molded coke further includes a material returning step, and the material returning step includes:

[0073] A bar screen is fixed at the discharge port of the ball press to transport the screened material to the buffer bin.

[0074] A bar screen is fixed at the dryer discharge port to transfer the screened material to the buffer bin. And,

[0075] The drying flue gas obtained in the drying step is subjected to water bath dust removal to obtain clean gas and dust-removed precipitate, the clean gas is discharged, and the dust-removed precipitate is mixed with coke powder as a raw material.

[0076] Specifically, when the briquette machine cold-presses the batch material to obtain wet coke, it is inevitable that some coke powder is not formed. A bar screen is fixed at the discharge port of the briquette machine, and the material on the screen is wet coke, which is sent to the next drying process, and the material under the screen is transported to the buffer bin for cold pressing again. During the drying process of the dryer, some coke breaks. Therefore, a bar screen is fixed at the discharge port of the dryer, and the material under the screen is transported to the buffer bin for cold pressing again, and the material on the screen is the coke product. This avoids the waste of coke powder and can also increase the output and yield of coke.

[0077] At the same time, the drying flue gas obtained in the drying step is subjected to water bath dust removal to obtain clean gas and dust removal precipitate, and the clean gas is discharged. Most of the dust removal precipitate is coke powder, and the dust removal precipitate is mixed with the coke powder as a raw material, which avoids the waste of coke powder and the subsequent cost consumption of treating the dust removal precipitate as solid waste, realizing the recycling of waste materials and reducing resource consumption, with good economic and environmental benefits.

[0078] The technical solution of the present application is described in detail below with reference to specific embodiments.

[0079] Example 1

[0080] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0081] 1) Mix coke powder with water to obtain wet coke powder. The particle size of the coke powder is ≤5mm.

[0082] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0083] The binder includes the following components in parts by weight:

[0084] 40 parts by weight of bentonite, 30 parts by weight of starch, 10 parts by weight of lignin, 5 parts by weight of sodium humate, 5 parts by weight of sodium carboxymethyl starch, 1 part by weight of straw powder, 0.5 parts by weight of quicklime, 0.5 parts by weight of sodium 2-naphthyloxyacetate and 0.2 parts by weight of didodecyl thiodipropionate. The starch is corn starch.

[0085] The water content of the binder is ≤0.2%, the amount of water added is 11% of the weight of the batch, and the amount of binder added is 4% of the weight of the batch.

[0086] The straw powder is obtained by drying the straw to a moisture content of ≤0.2%, and then crushing the straw into particles with a particle size of 3 by a crusher.

[0087] 3) The batch material is transported to the buffer bin, and the batch material is quantitatively output to the buffer output step of the ball press through the buffer bin.

[0088] 4) The batch material is pressurized by a briquette press to obtain the cold pressing step of wet coke. The pressure of the briquette press is 30MPa. A bar screen is fixed at the discharge port of the briquette press to transfer the screened material to the buffer bin.

[0089] 5) Desulfurize and denitrate the coke oven flue gas to obtain the flue gas to be dried, pass the flue gas to be dried into the dryer, dry the wet coke to obtain drying flue gas and coke, perform water bath dust removal on the drying flue gas to obtain clean gas and dust precipitate, discharge the clean gas, and mix the dust precipitate with coke powder as raw materials. Fix a bar screen at the dryer discharge port, and transfer the screened material to the buffer bin. The temperature of the flue gas to be dried is 180-190°C, and the water content of the obtained coke is less than 0.5%.

[0090] Example 2

[0091] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0092] The difference from Example 1 is that:

[0093] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0094] The binder includes the following components in parts by weight:

[0095] 43 parts by weight of bentonite, 31 parts by weight of starch, 13 parts by weight of lignin, 7 parts by weight of sodium humate, 5.5 parts by weight of sodium carboxymethyl starch, 1.5 parts by weight of straw powder, 0.7 parts by weight of quicklime, 0.7 parts by weight of sodium 2-naphthyloxyacetate and 0.25 parts by weight of didodecyl thiodipropionate. The starch is corn starch.

[0096] The moisture content of the binder is ≤0.2%, the amount of water added is 14% of the weight of the batch material, the amount of the binder added is 5% of the weight of the batch material, and the particle size of the crushed straw is 5 mm.

[0097] 4) The batch material is pressurized by a briquette press to obtain the cold pressing step of wet coke. The pressure of the briquette press is 35 MPa.

[0098] 5) Desulfurizing and denitrifying the coke oven flue gas to obtain flue gas to be dried, and passing the flue gas to be dried into a dryer to dry the wet coke to obtain drying flue gas and coke, wherein the moisture content of the coke is less than 0.5%.

[0099] Example 3

[0100] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0101] The difference from Example 1 is that:

[0102] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0103] The binder includes the following components in parts by weight:

[0104] 46 parts by weight of bentonite, 33 parts by weight of starch, 16 parts by weight of lignin, 9 parts by weight of sodium humate, 6 parts by weight of sodium carboxymethyl starch, 2 parts by weight of straw powder, 0.9 parts by weight of quicklime, 0.9 parts by weight of sodium 2-naphthyloxyacetate and 0.3 parts by weight of didodecyl thiodipropionate. The starch is corn starch.

[0105] The moisture content of the binder is ≤0.2%, the amount of water added is 17% of the weight of the batch material, the amount of the binder added is 6% of the weight of the batch material, and the particle size of the crushed straw is 7 mm.

[0106] 4) The batch material is pressurized by a briquette press to obtain the cold pressing step of wet coke. The pressure of the briquette press is 40 MPa.

[0107] 5) Desulfurizing and denitrifying the coke oven flue gas to obtain flue gas to be dried, and passing the flue gas to be dried into a dryer to dry the wet coke to obtain drying flue gas and coke, wherein the moisture content of the coke is less than 0.5%.

[0108] Example 4

[0109] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0110] The difference from Example 1 is that:

[0111] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0112] The binder includes the following components in parts by weight:

[0113] 50 parts by weight of bentonite, 35 parts by weight of starch, 20 parts by weight of lignin, 10 parts by weight of sodium humate, 7 parts by weight of sodium carboxymethyl starch, 3 parts by weight of straw powder, 1 part by weight of quicklime, 1 part by weight of sodium 2-naphthyloxyacetate and 0.4 parts by weight of didodecyl thiodipropionate. The starch is corn starch.

[0114] The moisture content of the binder is ≤0.2%, the amount of water added is 20% of the weight of the batch material, the amount of the binder added is 8% of the weight of the batch material, and the particle size of the crushed straw is 10 mm.

[0115] 4) The batch material is pressurized by a briquette press to obtain the cold pressing step of wet coke. The pressure of the briquette press is 40 MPa.

[0116] 5) Desulfurizing and denitrifying the coke oven flue gas to obtain flue gas to be dried, and passing the flue gas to be dried into a dryer to dry the wet coke to obtain drying flue gas and coke, wherein the moisture content of the coke is less than 0.5%.

[0117] Comparative Example 1

[0118] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0119] 5) Provide drying heat for the dryer through combustion heating.

[0120] Comparative Example 2

[0121] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0122] The difference from Example 3 is that:

[0123] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0124] The binder includes the following components in parts by weight:

[0125] 39 parts by weight of bentonite, 28 parts by weight of starch, 9 parts by weight of lignin, 4 parts by weight of sodium humate, 4 parts by weight of sodium carboxymethyl starch, 0.8 parts by weight of straw powder, 0.4 parts by weight of quicklime, 0.4 parts by weight of sodium 2-naphthyloxyacetate and 0.1 parts by weight of didodecyl thiodipropionate. The starch is corn starch.

[0126] Comparative Example 3

[0127] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0128] The difference from Example 3 is that:

[0129] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0130] The binder includes the following components in parts by weight:

[0131] 41 parts by weight of bentonite, 31 parts by weight of starch, 12 parts by weight of lignin, 6 parts by weight of sodium humate, 6 parts by weight of sodium carboxymethyl starch, 1.5 parts by weight of straw powder, 0.6 parts by weight of quicklime, 0.6 parts by weight of sodium 2-naphthyloxyacetate and 0.3 parts by weight of didodecyl thiodipropionate. The starch is corn starch.

[0132] Comparative Example 4

[0133] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0134] The difference from Example 3 is that:

[0135] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0136] The binder does not include straw powder and quicklime.

[0137] Comparative Example 5

[0138] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0139] The difference from Example 3 is that:

[0140] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0141] Sodium 2-naphthyloxyacetate is not included in the binder.

[0142] Comparative Example 6

[0143] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0144] The difference from Example 3 is that:

[0145] 2) The wet coke powder is mixed with a binder to obtain a mixing and stirring step of a batch material.

[0146] Didodecyl thiodipropionate was not included in the binder.

[0147] Comparative Example 7

[0148] The method for producing molded coke by utilizing coke powder resources in this embodiment has the following specific operation process:

[0149] The difference from Example 3 is that:

[0150] The straw powder is prepared by soaking the straw in 2-5% alkali solution for 5-7 hours, drying the straw until the moisture content is ≤ 0.2%, crushing the straw, mixing it with other components in the binder, and then mixing it with the coke powder.

[0151] Experimental Example 1

[0152] The heat of the drying heat source in the drying step in Comparative Example 1 was calculated and compared with that in Example 3:

[0153] Compared with the use of waste coke oven flue gas as a drying heat source in Comparative Example 1, the technical solution provided in Example 3 has a good energy-saving effect. According to the annual production scale of 200,000 tons of molded coke and 1600Kcal / kgH2O, the annual drying water required is: 33918.12t, and the required heat is: 1600×33918.12×1000=5.4269×10 10 Kcal, equivalent to energy-saving standard coal: 5.4269×10 10 / 7000=7.753×10 6 kgce=7753tce. Using the waste coke oven flue gas as the drying heat source can save 7753tce of standard coal in the coke production process every year, which has a good energy-saving effect and reduces the production cost of the enterprise.

[0154] Experimental Example 2

[0155] The performance of the molded coke produced by the technical solutions provided in Examples 1 to 4 and Comparative Examples 2 to 6 was tested. Since the molded coke is used as a substitute for coke in the production of ferroalloys, the fixed carbon content, ash content, volatile matter and room temperature resistivity of the molded coke were tested with reference to the industry standard "YB / T034-2015 Coke for Ferroalloys". At the same time, the compressive strength of the molded coke was tested by a compressive strength tester. The test results are shown in Table 1:

[0156] Table 1

[0157]

[0158] Observe Table 1, compare Examples 1 to 4 with Comparative Examples 2 to 6, and find that the addition of straw powder can also provide a certain carbon content for the coke, which helps to improve the combustion efficiency of the coke when it is used later. In addition, the content of each component in the binder of Comparative Example 2 is increased compared with that of Examples 1 to 4, but the fixed carbon content of the coke in Comparative Example 2 is not relatively increased, and the increase in the content of each component of the binder in Comparative Example 2 leads to an increase in the ash content, which is not conducive to the subsequent use of coke as a substitute for coke in the ferroalloy industry, which shows that the content of each component in the binder should be kept within a reasonable range. At the same time, it can be seen that Examples 1 to 4 all have good room temperature resistivity, and the larger the room temperature resistivity, the better for the lower electrode of the submerged arc furnace.

[0159] Experimental Example 3

[0160] The compressive strength and drop strength of the molded coke produced by the technical solutions provided in Examples 1 to 4 and Comparative Examples 2 to 6 were tested.

[0161] Drop strength test: Take an air-dried coke sample and weigh its initial weight as m1. Drop the sample naturally from a 100cm high mobile platform onto a horizontally placed 12mm thick steel plate. After the sample is dropped, it is sieved through a 13mm sieve. The weight of the remaining coke above the sieve is weighed as m2. Calculate the drop strength according to the following formula:

[0162] Drop strength = m2 / m1×100%.

[0163] The compressive strength test of molded coke refers to the industry standard "GB / T 14201-2018 Determination of compressive strength of iron pellets for blast furnace and direct reduction". The test results are shown in Table 2:

[0164] Table 2

[0165] Drop strength / % Compressive strength / N Example 1 99 1188 Example 2 98 1206 Example 3 99 1213 Example 4 98 1256 Comparative Example 1 99 1176 Comparative Example 2 94 997 Comparative Example 3 93 943 Comparative Example 4 92 745 Comparative Example 5 89 710 Comparative Example 2 86 698 Comparative Example 7 86 703

[0166] As can be seen from Table 2, the molded coke obtained in Examples 1 to 4 has good drop strength and compressive strength, which shows that the mechanical strength of the internal structure of the molded coke obtained by the molded coke production method provided by the present application is relatively strong. Compared with Examples 1 to 4, the mechanical strength of the molded coke is not greatly affected by different drying methods in Comparative Example 1. Compared with Examples 1 to 4, Comparative Examples 4 to Comparative Examples 6 show that the addition of a binder can improve the compactness between coke powders, wherein bentonite absorbs moisture in wet coke powder and expands to form a three-dimensional network structure, which increases the viscosity of the binder, and starch can improve adhesion when it meets water, thereby improving the adhesion between coke powder particles. The long chain structures between lignin molecules are intertwined, and can form a strong connection between coke powders, which is conducive to the compact structure of the internal structure of the molded coke. At the same time, quicklime generates alkaline calcium hydroxide when it meets water, and releases heat at the same time, opens the ester bonds in the straw powder, and expands the fibers in the straw powder, which increases the affinity between coke powder and straw powder, and between coke powder and coke powder, and synergizes with bentonite to improve the compactness between coke powders, thereby improving the strength of the molded coke. The addition of sodium carboxymethyl starch can generate a colloid with higher viscosity and increase the adhesion between coke powders when it comes into contact with water.

[0167] At the same time, compared with Examples 1 to 4, Comparative Examples 2-3 show that the content of each component in the binder must be maintained within a reasonable range in order to improve the structural strength of the molded coke. Although the addition of sodium carboxymethyl starch can generate a colloid with greater viscosity and improve the adhesion between coke powders after contacting water, it is easy to cause the dispersion degree of the binder in the coke powder to be low due to its high viscosity, which prolongs the time for stirring and mixing. The addition of straw powder just solves the problem of low dispersion. When straw powder is mixed with coke powder, it will not produce a large viscosity, and the straw powder has a certain particle size, which can increase the friction coefficient between the coke powder and the bentonite, starch, and sodium carboxymethyl starch in the binder during the mixing process, disperse the viscosity of sodium carboxymethyl starch, and make the binder more easily dispersed in the coke powder while playing a viscosity role, which not only improves the structural stability and structural strength of the molded coke.

[0168] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for producing molded coke by utilizing coke powder as a resource, characterized in that: The method comprises the following steps: 1) mixing coke powder with water to obtain wet coke powder; 2) a mixing and stirring step of mixing the wet coke powder with a binder to obtain a batch material; 3) a buffer output step of transferring the batch material to a buffer bin, and quantitatively outputting the batch material to a pellet press through the buffer bin; 4) Pressurizing the batch material by a briquette press to obtain a cold pressing step of wet coke; 5) Drying the wet coke in a dryer to obtain the coke; The drying step comprises: desulfurizing and denitrifying the coke oven flue gas to obtain the flue gas to be dried, passing the flue gas to be dried into the dryer, drying the wet coke to obtain drying flue gas and coke, and removing dust from the drying flue gas and discharging it; The binder comprises the following components in parts by weight: 40-50 parts by weight of bentonite, 30-35 parts by weight of starch, 10-20 parts by weight of lignin, 5-10 parts by weight of sodium humate, 5-7 parts by weight of sodium carboxymethyl starch, 1-3 parts by weight of straw powder, 0.5-1 parts by weight of quicklime, 0.5-1 parts by weight of sodium 2-naphthyloxyacetate and 0.2-0.4 parts by weight of didodecyl thiodipropionate.

2. The method for producing molded coke by utilizing coke powder as a resource according to claim 1, characterized in that: The particle size of the coke powder is ≤5mm.

3. The method for producing molded coke by utilizing coke powder as a resource according to claim 1, characterized in that: The amount of water added is 11-20% of the weight of the batch material, and the amount of the binder added is 4-8% of the weight of the batch material.

4. The method for producing molded coke by utilizing coke powder as a resource according to claim 1, characterized in that: The starch is one or more of corn starch, potato starch and tapioca starch.

5. The method for producing molded coke by utilizing coke powder as a resource according to claim 4, characterized in that: The temperature of the flue gas to be dried is 180-190°C.

6. The method for producing molded coke by utilizing coke powder as a resource according to claim 5, characterized in that: In the cold pressing step, the pressure of the ball press is 30-40MPa.

7. The method for producing molded coke by utilizing coke powder as a resource according to any one of claims 1 to 6, characterized in that: The step of returning the material is also included, and the step of returning the material includes: A bar screen is fixed at the discharge port of the ball press to transport the screened material to the buffer bin; A bar screen is fixed at the discharge port of the dryer to transport the screened material to the buffer bin; and The drying flue gas obtained in the drying step is subjected to water bath dust removal to obtain clean gas and dust removal precipitate, the clean gas is discharged, and the dust removal precipitate is mixed with the coke powder as a raw material.

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