Solid fuel reheat steam treatment system

Abstract

Disclosed is a solid fuel reheat steam treatment system. The solid fuel reheat steam treatment system according to the present invention includes a pretreatment unit to which a solid fuel is supplied to spray a bio-liquid onto the solid fuel, thereby impregnating the solid fuel with the bio-liquid; a heat treatment unit to which the solid fuel impregnated with the bio-liquid is supplied to perform a heat treatment on the solid fuel impregnated with the bio-liquid; a reheat steam supply unit for supplying reheat steam to the heat treatment unit to directly heat the solid fuel supplied into the heat treatment unit; a cooling unit to which the solid fuel heat-treated by the heat treatment unit is supplied to cool the solid fuel; and a coolant supply unit for supplying a coolant to the cooling unit to cool the solid fuel supplied into the cooling unit.

Description

Technical Field

[0001] This invention relates to a solid fuel reheat steam treatment system. Background Technology

[0002] For example, in a thermal power plant that uses solid fuels such as coal, approximately 180 tons of coal are burned per 500 MW, which is equivalent to about 37 tons of coal being supplied to the boiler for each pulverizer.

[0003] A 500-megawatt coal-fired power plant includes approximately six coal storage silos with a capacity of approximately 500 tons each. Five of these silos are used for normal coal supply, while the remaining silo is used as a storage silo to store coal intended for use in emergency situations within a predetermined time period.

[0004] Furthermore, coal-fired power plants that use coal as fuel are designed to meet standard coal power design standards, which require bituminous coal with a low moisture content of 6,080 kcal / kg and less than 10%. However, some coal-fired power plants use imported coal, some of which has an average moisture content of over 17%, which reduces boiler combustion efficiency.

[0005] When the calorific value of the coal used is low, with a standard power combustion limit of 5,400 kcal / kg, reduced combustion efficiency is expected, leading to decreased power generation and increased fuel consumption. Furthermore, when using lignite with high moisture content (above 25%) and low calorific value, the higher-than-design-standard moisture content causes problems with coal transport systems, resulting in reduced efficiency in coal grinding using pulverizers, reduced combustion efficiency due to incomplete combustion, uneven heat distribution within the boiler, and abnormal operation. However, in thermal power plants, the use of lignite has gradually increased to approximately 41% to 60% to reduce fuel costs, and solid fuels such as coal are indirectly heated and dried by supplying high-pressure steam to the jacket or pipelines through steam dryers.

[0006] However, when a steam dryer is used to dry solid fuels such as coal at high temperatures with hot air at or above a predetermined temperature, volatile gases and fine particles are generated. When these volatile gases and fine particles reach the combustion temperature, they ignite and burn in the equipment.

[0007] In other words, when using high-temperature dry air (oxygen concentration of 21%) that has undergone heat exchange, drying proceeds quickly, but combustibles can ignite. Therefore, to prevent combustibles from igniting, dry air at very low temperatures (60°C to 80°C) is used to dry the combustibles, or indirect drying is performed through contact with the surface of a steam pipe to prevent direct contact with high-temperature hot air.

[0008] However, cryogenic air or indirect drying based on heat transfer requires a long time and very large equipment size, resulting in excessive energy consumption.

[0009] Meanwhile, interest in coal as an energy source has been increasing recently due to the continued rise in oil prices and distrust in the stability of nuclear energy. However, coal produces the most carbon dioxide among fossil fuels, making it a less competitive energy source in light of global warming. Therefore, the development and utilization of renewable energy sources is currently a global issue, and renewable energy is a viable option for addressing global warming and climate change because it reduces carbon dioxide emissions compared to fossil fuels such as oil and coal.

[0010] Compared to fossil fuels, renewable energy sources used for power generation or heating (such as solar or wind power) have limited development and utilization due to differences in power generation costs. However, with the depletion of fossil fuels and the reduction of greenhouse gas emissions in response to international treaties and climate change conventions, the Renewable Energy Portfolio Standard (RPS) was proposed and introduced in 2012, and is becoming a burden for domestic energy producers.

[0011] Therefore, power companies are experimenting with integrated gasification combined cycle (IGCC) and biomass blending in an effort to reduce carbon dioxide emissions from coal.

[0012] However, IGCC cannot use existing coal-fired power plants. Each coal-fired power plant requires a high construction cost of approximately 1.3 trillion won and also requires the additional installation of carbon capture and storage (CCS) systems to remove carbon dioxide, which would create a very large economic burden.

[0013] In the case of biomass blends, power generation efficiency decreases because biomass burns at a lower calorific value than coal. In the case of a blend of coal and oil-based biomass, the coal surface is coated with oil or the pores on the coal surface are impregnated with oil. However, due to the low surface tension of oil itself and the weak bonding between oil-based biomass and the coal surface, coal and biomass each retain their own combustion characteristics, resulting in different combustion properties. Therefore, in power plant applications, the excessive oxygen in the low-temperature combustion mode of oil burns first at the burner front, ultimately inhibiting coal combustion, leading to increased unburned carbon and reduced power generation efficiency.

[0014] Therefore, in order to promote the development and utilization of renewable energy and ensure the stability of biomass fuel supply, it is necessary to research and develop the use of biomass-derived materials to improve low-rank coal.

[0015] [Related Literature]

[0016] [Reference 1] Korean Patent No. 10-1860037

[0017] [Reference 2] Korean Patent No. 10-1195416 Summary of the Invention

[0018] Technical issues

[0019] Therefore, the present invention aims to provide a solid fuel reheat steam treatment system for improving solid fuels, which effectively dries and heat-treats solid fuels by impregnating or coating them with a bio-liquid comprising liquid components (including glucose and xylose and / or lignin) and directly heating the solid fuels with high-temperature reheat steam.

[0020] Technical solution

[0021] According to one aspect of the present invention, a solid fuel reheat steam treatment system is provided, comprising: a pretreatment unit to which solid fuel is supplied for spraying a bio-liquid onto the solid fuel, thereby impregnating the solid fuel with the bio-liquid; a heat treatment unit to which the bio-liquid-impregnated solid fuel is supplied for heat treatment; a reheat steam supply unit to which reheat steam is supplied to the heat treatment unit for directly heating the solid fuel supplied to the heat treatment unit; a cooling unit to which the heat-treated solid fuel is supplied to the cooling unit for cooling; and a coolant supply unit to which coolant is supplied to the cooling unit for cooling the solid fuel supplied to the cooling unit.

[0022] The pretreatment unit may include: a first body to which solid fuel is supplied; a bio-liquid injection unit disposed within the first body to inject bio-liquid onto the solid fuel supplied to the first body; and a bio-liquid supply unit connected to the bio-liquid injection unit to supply bio-liquid to the bio-liquid injection unit.

[0023] The bio-liquid injection unit may include at least one bio-liquid injection pipe, each bio-liquid injection pipe including a plurality of first nozzles arranged along the length of the first body to inject bio-liquid.

[0024] The first body may include a cylindrical rotary furnace rotating at a predetermined speed.

[0025] The heat treatment unit may include: a second body into which solid fuel impregnated with bio-liquid is supplied; and a reheat steam injection unit disposed at the outlet of the second body to inject reheat steam supplied from the reheat steam supply unit into the second body.

[0026] The reheat steam injection unit may include: a reheat steam supply unit, the reheat steam supply unit including a plurality of reheat steam channels, each of the plurality of reheat steam channels being connected to a reheat steam nozzle at its end; a reheat steam injection plate, the reheat steam nozzle being embedded in the reheat steam injection plate; and a reheat steam main nozzle, the reheat steam main nozzle being connected to the reheat steam channel and formed at the central axis of the reheat steam injection plate.

[0027] The reheat steam injection unit may further include: a reheat steam bending member for guiding reheat steam along the periphery of the end of the reheat steam injection plate toward the center of the second body; and a reheat steam turbulence forming member formed between the reheat steam bending member and the end of the reheat steam injection plate to induce turbulence in the injected reheat steam.

[0028] The cooling unit may include: a third body into which solid fuel, which is heat-treated by the heat treatment unit, is supplied; a jacket disposed around the third body; and a coolant injection unit disposed between the third body and the jacket to inject coolant onto the outer surface of the third body.

[0029] The coolant injection unit may include at least one coolant injection pipe, each coolant injection pipe including a plurality of second nozzles arranged along the length of the third body between the third body and the jacket to inject coolant.

[0030] The cooling unit may further include a water tank disposed below the jacket to store coolant discharged through the outlet of the jacket, thereby circulating the coolant sprayed by the coolant injection unit to the coolant supply unit.

[0031] The solid fuel reheat steam treatment system may further include: an impurity removal unit configured to remove impurities contained in steam discharged from the heat treatment unit; a blower unit configured to circulate steam passing through the impurity removal unit to a reheat steam supply unit; and an exhaust unit configured to exhaust steam passing through the blower unit in an amount equal to the steam flow generated during the heat treatment of the solid fuel by the heat treatment unit.

[0032] The impurity removal unit may include at least one cyclone separator and at least one bag filter, the bag filter being connected to the cyclone separator.

[0033] The solid fuel reheat steam treatment system may further include: a pulverizing unit configured to pulverize solid fuel; a separation unit configured to separate solid fuel pulverized by the pulverizing unit with an average particle size of less than 6 mm; and a storage unit configured to store the solid fuel separated by the separation unit, and the solid fuel stored in the storage unit may be supplied to a pretreatment unit.

[0034] The solid fuel reheat steam treatment system may further include a conveying unit disposed between the storage unit and the pretreatment unit for conveying the solid fuel stored in the storage unit to the pretreatment unit.

[0035] The conveying unit may include: a first screw feeder configured to convey solid fuel stored in a storage unit; a bucket in which the solid fuel conveyed by the first screw feeder is contained; and a lift connected to the lift to raise the bucket in a height direction, the bucket being able to be raised by the lift, and the solid fuel contained in the raised bucket being able to be supplied to a pretreatment unit.

[0036] Beneficial effects

[0037] Embodiments of the present invention can improve the calorific value of solid fuels by impregnating or coating the micropores of solid fuels with a bio-liquid comprising liquid components (including glucose and xylose and / or lignin) and then drying and heat-treating the solid fuels.

[0038] In addition, embodiments of the present invention can effectively dry and heat-treat solid fuels by directly heating them with high-temperature reheat steam to impregnate or coat them with biological liquids.

[0039] In addition, embodiments of the present invention can use high-temperature reheat steam to directly heat-treat solid fuel to prevent ignition and reduce drying and heat treatment time. Attached Figure Description

[0040] Figure 1 This is a schematic diagram illustrating the architecture of a solid fuel reheat steam treatment system according to the present invention.

[0041] Figure 2 This is a diagram illustrating a solid fuel reheat steam treatment system according to the present invention.

[0042] Figure 3 This is an enlarged view showing the crushing unit and the separating unit according to the present invention.

[0043] Figure 4 This is an enlarged view showing the storage unit, conveying unit, and preprocessing unit according to the present invention.

[0044] Figure 5 This is an enlarged view showing the heat treatment unit, impurity removal unit, blower unit, discharge unit and reheat steam supply unit according to the present invention.

[0045] Figure 6 This is a front view showing the reheat steam injection unit according to the present invention.

[0046] Figure 7 This is a side sectional view showing the reheat steam injection unit according to the present invention.

[0047] Figure 8 This is an enlarged view showing the cooling unit and coolant supply unit according to the present invention.

[0048] Figure 9 This is a table showing approximate analysis, limit analysis, high calorific value, and low calorific value before and after solid fuel is treated by the solid fuel reheat steam treatment system according to the present invention.

[0049] Figure 10 It is a graph showing the auto-ignition (combustion) temperature of solid fuel before it is treated by the solid fuel reheat steam treatment system according to the present invention.

[0050] Figure 11 It is a graph showing the auto-ignition (combustion) temperature of solid fuel after it has been treated by the solid fuel reheat steam treatment system according to the present invention. Detailed Implementation

[0051] To fully understand the present invention, its advantages, and the objectives achieved by its embodiments, please refer to the accompanying drawings, which illustrate exemplary embodiments of the invention and the scenarios described therein.

[0052] In the following description, the invention will be described in detail with reference to the accompanying drawings, which depict exemplary embodiments of the invention. The same reference numerals in each figure denote the same elements.

[0053] Figure 1 This is a schematic diagram illustrating the architecture of a solid fuel reheat steam treatment system according to the present invention. Figure 2 This is a diagram illustrating a solid fuel reheat steam treatment system according to the present invention. Figure 3 This is an enlarged view showing the crushing unit and the separating unit according to the present invention. Figure 4 This is an enlarged view showing the storage unit, conveying unit, and preprocessing unit according to the present invention. Figure 5 This is an enlarged view showing the heat treatment unit, impurity removal unit, blower unit, discharge unit, and reheat steam supply unit according to the present invention. Figure 6 This is a front view showing the reheat steam injection unit according to the present invention. Figure 7This is a side sectional view showing the reheat steam injection unit according to the present invention. Figure 8 This is an enlarged view showing the cooling unit and coolant supply unit according to the present invention.

[0054] Reference Figures 1 to 8 The solid fuel reheat steam treatment system 100 according to the present invention includes: a pulverizing unit 110 for pulverizing solid fuel; a separation unit 115 for separating the solid fuel pulverized by the pulverizing unit 110 according to a predetermined particle size requirement; a storage unit 118 for storing the solid fuel separated by the separation unit 115; a pretreatment unit 130, wherein the solid fuel stored in the storage unit 118 is supplied to the pretreatment unit 130 to spray a bio-liquid comprising a liquid component containing glucose and xylose and / or lignin onto the solid fuel for impregnation with the bio-liquid; and a heat treatment unit. 140, solid fuel impregnated with bio-liquid is supplied from pretreatment unit 130 to heat treatment unit 140 for heat treatment of the solid fuel impregnated with bio-liquid; reheat steam supply unit 160 is used to supply reheat steam to heat treatment unit 140 to directly heat the solid fuel supplied to heat treatment unit 140; cooling unit 170 is used to cool the solid fuel heat-treated by heat treatment unit 140; and coolant supply unit 180 is used to supply coolant to cooling unit 170 to cool the solid fuel supplied to cooling unit 170.

[0055] In this embodiment, the solid fuel may be selected from at least one of low-rank coal, such as peat, lignite, sub-bituminous coal, bituminous coal, and anthracite. The solid fuel may also include biomass and combustible waste. Furthermore, in this embodiment, the solid fuel is not limited to these categories and includes any type of solid fuel having a calorific value suitable for use as boiler fuel.

[0056] Reference Figure 2 and Figure 3 Since the solid fuels supplied as raw materials vary in size, it is necessary to reduce the average particle size of the solid fuels before supplying them to the pretreatment unit 130 and heat treatment unit 140 described below. Therefore, in this embodiment, the system includes a pulverizing unit 110 for pulverizing the solid fuels and a separation unit 115 for separating the pulverized solid fuels according to predetermined particle size requirements.

[0057] The pulverizing unit 110 pulverizes the solid fuel supplied as raw material. For this purpose, the pulverizing unit 110 includes a pulverizer 111 to pulverize the solid fuel. In addition, the solid fuel pulverized by the pulverizing unit 110 is supplied to a separation unit 115 located nearby.

[0058] The particle size requirements for solid fuels are necessary to improve the drying and heat treatment efficiency of solid fuels by impregnating or coating them with biological liquids through the pretreatment unit 130 and through the heat treatment unit 140.

[0059] In this embodiment, the average particle size standard for the solid fuel is preferably below 6 mm. Pulverized solid fuel larger than the average particle size standard is re-supplying to the pulverizer 111. Without classifying the solid fuel according to the average particle size standard, it is difficult to achieve the desired impregnation or coating effect, as well as uniform drying and heat treatment.

[0060] Solid fuels with a particle size of less than 6 mm and solid fuels with a particle size greater than 6 mm are separated by the separation unit 115 and stored separately. As described above, solid fuels with a particle size greater than 6 mm can be supplied to the crusher 111 and crushed again.

[0061] Meanwhile, solid fuel with a particle size equal to or less than 6 mm is stored in storage unit 118 and supplied to pretreatment unit 130 as described below.

[0062] Reference Figure 2 and Figure 4 The pretreatment unit 130 impregnates or coats solid fuel with a bio-liquid by spraying it onto the fuel. In this embodiment, the bio-liquid comprises liquid components including glucose, xylose, and / or lignin. The pretreatment unit 130 improves low-calorific-value, low-grade solid fuels into high-calorific-value solid fuels.

[0063] In this embodiment, the biological liquid is prepared into a solution with a specified concentration using a liquid component containing glucose and xylose and / or a liquid component containing lignin.

[0064] The concentration of the biological fluid represents the solution ratio of the supplied liquid component to the total biological fluid, and can be greater than 0 and less than 1. Preferably, the concentration of the biological fluid can be 0.3 or more and 0.95 or less, more preferably 0.5 or more and 0.9 or less.

[0065] When the concentration of the biological liquid is higher than 0.9, it is difficult to spray due to its high viscosity, while when the concentration of the biological liquid is lower than 0.5, it requires higher processing costs due to its high water content.

[0066] The pretreatment unit 130 includes: a first body 131 to which solid fuel is supplied; a bio-liquid injection unit 132 disposed inside the first body 131 to inject bio-liquid onto the solid fuel supplied to the first body 131; and a bio-liquid supply unit 135 connected to the bio-liquid injection unit 132 to supply bio-liquid to the bio-liquid injection unit 132.

[0067] The bio-liquid injection unit 132 includes at least one bio-liquid injection pipe 132 having a plurality of first nozzles 133 arranged within a first body 131 along the length of the first body 131 to inject bio-liquid. Additionally, the bio-liquid supply unit 135 includes: a bio-liquid storage tank 136 therein for storing bio-liquid; and a pump 137 connected to the bio-liquid storage tank 136 to supply the bio-liquid stored in the bio-liquid storage tank 136 to the bio-liquid injection pipe 132.

[0068] The first body 131 may include a cylindrical rotary kiln rotating at a predetermined speed. The first body 131 rotates clockwise or counterclockwise via a first drive unit (not shown). Solid fuel moving upward along the inner wall of the first body 131 falls and slides downward within the first body 131 at an angle of repose or greater than the angle of repose. When the first body 131 rotates, the solid fuel rotates within the first body 131 and moves toward the outlet.

[0069] Furthermore, the first body 131 includes a plurality of blades (not shown) for smoothly moving solid fuel. The blades enable the solid fuel supplied to the first body 131 to move smoothly.

[0070] As the first body 131 rotates, the blades cause the solid fuel to rise and fall at a predetermined position, and the shape of each blade and the falling position of the solid fuel can be different.

[0071] The solid fuel is repeatedly dropped at a predetermined position by the rotation of the first body 131 and the blades, and this is called the waterfall effect because it looks like a waterfall of water. As the solid fuel moves upward and falls, the surface of the solid fuel is exposed, and the solid fuel is uniformly impregnated or coated with biological liquid by spraying biological liquid onto the exposed surface.

[0072] In other words, as the solid fuel moves within the first body 131, the bio-liquid is sprayed onto the solid fuel through a plurality of first nozzles 133 formed in the bio-liquid injection pipe 132. The bio-liquid injection pipe 132 can pass through the first body 131 along its length. The pump 137 of the bio-liquid supply unit 135 supplies bio-liquid to the bio-liquid injection pipe 132 and sprays the bio-liquid onto the solid fuel through the plurality of first nozzles 133.

[0073] Meanwhile, the system may include a conveying unit 120, which is located between the storage unit 118 and the pretreatment unit 130 to convey solid fuel stored in the storage unit 118 to the pretreatment unit 130.

[0074] The conveying unit 120 includes: a first screw feeder 121 for conveying solid fuel stored in the storage unit 118; a bucket 123 therein containing the solid fuel conveyed by the first screw feeder 121; and a lift 125 connected to the bucket 123 to raise the bucket 123 in the height direction.

[0075] When solid fuel stored in storage unit 118 is supplied to the first screw feeder 121, the solid fuel is conveyed by the first screw feeder to bucket 123 and contained in bucket 123. When solid fuel is contained in bucket 123, bucket 123 is located at the lower part of elevator 125, and when solid fuel is contained in bucket 123, bucket 123 moves upward in the height direction via elevator 125 and is fed into the first body 131 of pretreatment unit 130.

[0076] As described above, when the first body 131 rotates, the solid fuel rotates within the first body 131 and moves toward the outlet (i.e., toward the heat treatment unit 140 described below), and while the solid fuel moves, it is impregnated or coated with biological liquid.

[0077] However, when solid fuel is impregnated or coated with a bio-liquid, the micropores of the solid fuel are impregnated or coated with the bio-liquid. However, since the surfaces of the bio-liquid and the solid fuel are hydrophilic or have a strong affinity for water, the quality of the solid fuel decreases due to the adsorption of water from the air. To prevent this, an additional process is required. Therefore, a hydrophobication process can be performed to prevent water adsorption on the solid fuel impregnated or coated with the bio-liquid, and this process can be accomplished by drying and heat-treating the solid fuel impregnated or coated with the bio-liquid. Therefore, in this embodiment, the solid fuel impregnated or coated with the bio-liquid within the first body 131 is supplied to the heat treatment unit 140 and dried and heat-treated.

[0078] Additionally, the solid fuel impregnated or coated with bio-liquid discharged from the pretreatment unit 130 can be supplied to the heat treatment unit 140 via the second screw feeder 190.

[0079] Reference Figure 2 and Figures 5 to 7 The heat treatment unit 140 dries and heat-treats solid fuel impregnated or coated with biological liquid by direct heating.

[0080] The heat treatment unit 140 includes: a second body 141 into which solid fuel impregnated with biological liquid is supplied; and a reheat steam injection unit 142 disposed at the outlet of the second body 141 to inject reheat steam supplied from the reheat steam supply unit 160 as described below into the second body 141.

[0081] The second body 141 may include a cylindrical rotary kiln rotating at a predetermined speed. The second body 141 rotates clockwise or counterclockwise via a second drive unit (not shown). Solid fuel moving upwards along the inner wall of the second body 141 falls and slides downwards within the second body 141 at an angle of repose or greater. As the second body 141 rotates, the solid fuel rotates within the second body 141 and is dried as it moves toward the outlet.

[0082] Furthermore, the second body 141 includes a plurality of blades (not shown) for smooth movement of the solid fuel. The blades enable the solid fuel supplied to the second body 141 to move smoothly.

[0083] As the second body 141 rotates, the blades lift the solid fuel and drop it at a predetermined position, and the shape of each blade and the drop position of the solid fuel can be different.

[0084] As the solid fuel moves upward and falls repeatedly, its surface is exposed, and it is dried and heat-treated by contact with reheated steam. Simultaneously, the second drive unit includes rollers to rotate the second body 141 while maintaining close contact with the outer wall of the second body 141.

[0085] Additionally, a reheat steam injection unit 142 is disposed at the outlet of the second body 141 to inject reheat steam to directly heat the reheat steam while the solid fuel moves within the second body 141. The reheat steam injection unit 142 injects reheat steam in the direction of movement of the solid fuel. The reheat steam injected onto the second body 141 by the reheat steam injection unit 142 can be between 300°C and 500°C.

[0086] When the temperature of the reheat steam is maintained between 300°C and 500°C, it is easy to transfer heat to the solid fuel. This prevents the water contained in the solid fuel from being re-adsorbed into the micropores of the solid fuel after evaporation, thus making it easier to transport and store the solid fuel and obtain improved solid fuel with a high calorific value.

[0087] After measuring the internal pressure of the second body 141, the steam generated during the drying and heat treatment of the solid fuel is discharged through the discharge unit 158 ​​as described below.

[0088] When reheated steam at 300°C to 500°C is used, the solid fuel changes from hydrophilic to hydrophobic through surface modification. Even when exposed to air and in direct contact with moisture (e.g., rainwater), the solid fuel does not become wet again, thus facilitating external storage. Furthermore, the hydrophobic nature of the solid fuel prevents spontaneous combustion in air.

[0089] Additionally, by heat treatment of solid fuel impregnated or coated with biological liquid as described above, for example, heat treatment using reheat steam, low-rank coal can be transformed to have the calorific value characteristics of high-rank coal (see [link]). Figure 9 Therefore, when modified upgraded coal is used as fuel for power generation, high-rank coal can be used in existing power plants and environmental impacts such as greenhouse gas emissions can be reduced.

[0090] Furthermore, because the combustion temperature of dried and heat-treated solid fuels is increased, spontaneous combustion will not occur (see...). Figure 10 and Figure 11 ).

[0091] When solid fuel is kept outside during the summer, it may spontaneously combust due to the increased internal temperature. However, as described in this embodiment, when the solid fuel is dried and heat-treated by high-temperature reheat steam in the heat treatment unit 140, the combustion temperature increases, so spontaneous combustion will not occur even if the dried and heat-treated solid fuel is kept under the same conditions.

[0092] Furthermore, when solid fuel is dried and heat-treated, its surface becomes hydrophobic, thus preventing moisture re-adsorption. Additionally, when the surface of the solid fuel becomes hydrophobic, the contact angle between water droplets on the surface can be greater than 30°.

[0093] The reheat steam injection unit 142 includes: a reheat steam supply unit 143 having a plurality of reheat steam channels, each of which is connected to a reheat steam nozzle 148 at its end; a reheat steam injection plate 144 in which the reheat steam nozzles 148 are embedded; and a reheat steam main nozzle 145 connected to the reheat steam channels and formed at the central axis of the reheat steam injection plate 144.

[0094] Additionally, the reheat steam injection unit 142 may further include: a reheat steam bending member 146 for guiding reheat steam to be injected along the periphery of the end of the reheat steam injection plate 144 toward the center of the second body 141; and a reheat steam turbulence forming member 147 formed between the reheat steam bending member 146 and the end of the reheat steam injection plate 144 to induce turbulence in the injected reheat steam.

[0095] The injection pressure of the reheat steam nozzle 148 is preferably between 100 mm H2O and 500 mm H2O. High-pressure reheat steam is injected directly onto the supplied solid fuel, and since the small particles and dust generated at this time diffuse and are discharged from the impurity removal unit 150 as described below, it is necessary to switch to low-pressure reheat steam.

[0096] Meanwhile, the steam generated during the drying and heat treatment of the solid fuel by the heat treatment unit 140 (specifically the second body 141) is discharged from the second body 141, and the impurities contained in the steam discharged from the second body 141 are removed by the impurity removal unit 150.

[0097] The impurity removal unit 150 may include at least one cyclone separator 151 and at least one bag filter 152 in communication with the cyclone separator 151. Additionally, steam passing through the impurity removal unit 150 is supplied to a reheat steam supply unit 160. A blower unit 155 is disposed at the rear end of the impurity removal unit 150 to supply and circulate the steam passing through the impurity removal unit 150 to the reheat steam supply unit 160.

[0098] In addition, a portion of the steam passing through the impurity removal unit 150 is discharged through the discharge unit 158. Since the steam passing through the impurity removal unit 150 also includes steam generated during the drying and heat treatment of solid fuels, the excess steam discharged through the discharge unit 158 ​​is as much as the increased steam flow during the drying and heat treatment processes.

[0099] In this embodiment, when reheat steam is supplied to the heat treatment unit 140 via the reheat steam supply unit 160, preheating is performed by measuring the oxygen concentration in the reheat steam until the oxygen concentration is below 5%. When preheating is complete and the oxygen concentration in the reheat steam is below 5%, the reheat steam is supplied to the heat treatment unit 140.

[0100] As described above, in this embodiment, the heat treatment unit 140, the impurity removal unit 150, the blower unit 155, and the reheat steam supply unit 160 recover energy in a closed-loop cycle, thereby improving energy efficiency.

[0101] In addition, the solid fuel dried and heat-treated by the heat treatment unit 140 is supplied to the cooling unit 170.

[0102] When solid fuel is supplied, cooling unit 170 cools the dried and heat-treated solid fuel.

[0103] The cooling unit 170 includes: a third body 171 into which solid fuel, heat-treated by the heat treatment unit 140, is supplied; a jacket 172 disposed around the third body 171; a coolant injection unit 176 disposed between the third body 171 and the jacket 172 to inject coolant onto the outer surface of the third body 171; and a water tank 178 disposed below the jacket 172 to store coolant discharged through the outlet 175 of the jacket 172, thereby circulating the coolant injected by the coolant injection unit 176 to the coolant supply unit 180. Additionally, the coolant injection unit 176 includes at least one coolant injection pipe 176, each coolant injection pipe 176 including a plurality of second nozzles 177 arranged along the length of the third body 171 between the third body 171 and the jacket 172 to inject coolant.

[0104] The third body 171 may include a cylindrical rotary kiln rotating at a predetermined speed.

[0105] The third body 171 rotates clockwise or counterclockwise via the third drive unit (not shown). Solid fuel moving upward along the inner wall of the third body 171 falls and slides downward within the third body 171 at an angle of repose or greater.

[0106] As the third body 171 rotates, the solid fuel rotates within the third body 171 and is cooled as it moves toward the outlet 175.

[0107] Additionally, the third body 171 includes multiple blades (not shown) for the smooth movement of solid fuel. The blades enable the solid fuel supplied to the third body 171 to move smoothly.

[0108] As the third body 171 rotates, the blades lift the solid fuel and drop it at a predetermined position, and the shape of each blade and the drop position of the solid fuel can be different. When the upward movement and drop of the solid fuel are repeated, the surface of the solid fuel is exposed and cooling is promoted by the internal temperature of the third body 171.

[0109] Additionally, as the solid fuel moves within the third body 171, the third body 171 is cooled to cool the solid fuel within it. That is, the solid fuel is cooled indirectly by supplying coolant to the jacket 172 to cool the third body 171.

[0110] The jacket 172 includes: a housing 173 disposed around the third body 171 to form a cooling space S between the housing 173 and the outer wall of the third body 171; an inlet 174 disposed on the housing 173, into which coolant supplied to the coolant supply unit 180 enters; and an outlet 175 disposed below the housing 173 and opposite to the inlet 174, through which coolant exits the inlet 174 via the cooling space S.

[0111] Additionally, at least one coolant injection pipe 176 is provided in the cooling space S between the third body 171 and the jacket 172. The coolant injection pipe 176 includes a plurality of second nozzles 177 arranged along the length direction of the third body 171. Coolant supplied by the coolant supply unit 180 is supplied to the coolant injection pipe 176 through the inlet 174 of the jacket 172 and is sprayed into the cooling space S through the plurality of second nozzles 177.

[0112] Coolant supplied by coolant supply unit 180 enters inlet 174, is sprayed through coolant injection pipe 176, passes through cooling space S provided in housing 173 and exits outlet 175 provided below housing 173.

[0113] When the coolant cools the outer surface of the third body 171 through the cooling space of the cooling shell 173, the internal temperature of the third body 171 is reduced by heat transfer and the solid fuel supplied to the third body 171 is cooled down.

[0114] Additionally, the coolant discharged through outlet 175 of housing 173 is stored in water tank 178 and is supplied and circulated to coolant supply unit 180.

[0115] Meanwhile, the solid fuel cooled by the cooling unit 170 can be discharged by the third screw feeder 195.

[0116] The following comparison is made between low-rank raw coal and coal modified by the solid fuel reheat steam treatment system 100 according to the present invention.

[0117] Figure 9 This is a table showing approximate analysis, limiting analysis, high calorific value, and low calorific value before and after processing solid fuel by the solid fuel reheat steam treatment system according to the present invention. Figure 10 This is a graph showing the auto-ignition (combustion) temperature of solid fuel before it is treated by the solid fuel reheat steam treatment system according to the invention. Figure 11 It is a graph showing the auto-ignition (combustion) temperature of solid fuel after it has been treated by the solid fuel reheat steam treatment system according to the present invention.

[0118] Reference Figure 9 When using the solid fuel reheat steam treatment system 100 according to the present invention, upgraded coal with moisture contents of 0.46 wt% and 0.83 wt% is obtained by drying and heat-treating raw coal with moisture contents of 30 wt% and 26.19 wt% before treatment, respectively. Furthermore, when using the solid fuel reheat steam treatment system 100 according to the present invention, it can be seen that the calorific value and calorific value of the upgraded coal after treatment are both increased compared to the calorific value and calorific value of the raw coal before treatment.

[0119] Additionally, when using the solid fuel reheat steam treatment system 100 according to the present invention, the auto-ignition temperature of the raw coal before treatment is 163°C (see...). Figure 10 The temperature was raised to the auto-ignition temperature of the treated upgraded coal, which was 214℃ (see [reference]). Figure 11 Therefore, it can reduce the risk of spontaneous combustion during fuel storage and transportation.

[0120] This invention is not limited to the disclosed embodiments, and it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Therefore, it should be noted that such modifications or variations fall within the scope of the claims of this invention.

[0121] [Detailed Description of Major Components]

[0122] 100: Solid fuel reheat steam processing system

[0123] 110: Crushing Unit

[0124] 111: Crusher; 115: Separation device

[0125] 118: Storage unit; 120: Conveying unit

[0126] 121: First screw feeder; 123: Bucket

[0127] 125: Elevator; 130: Pre-processing unit

[0128] 131: First Main Body 132: Bio-liquid Jetting Unit

[0129] 135: Bio-liquid supply unit; 136: Bio-liquid storage tank

[0130] 137: Pump; 140: Heat treatment unit

[0131] 141: Second main body; 142: Reheat steam injection unit

[0132] 143: Reheat Steam Supply Unit; 144: Reheat Steam Injector Plate

[0133] 145: Reheat Steam Main Nozzle

[0134] 146: Reheat Steam Bending Components

[0135] 147: Reheat Steam Turbulence Formation Component

[0136] 148: Reheat Steam Nozzle

[0137] 150: Impurity removal unit; 151: Cyclone separator

[0138] 152: Bag filter; 155: Blower unit

[0139] 158: Discharge unit; 160: Reheat steam supply unit

[0140] 170: Cooling unit 171: Third main body

[0141] 172: Jacket; 176: Coolant injection unit

[0142] 178: Water tank; 180: Coolant supply unit

[0143] 190: Second screw feeder; 195: Third screw feeder

[0144] [Industrial Applications]

[0145] The solid fuel reheat steam treatment system according to the present invention can convert low-rank solid fuels into upgraded solid fuels with increased calorific value.

Claims

1. A solid fuel reheat steam processing system, comprising: In the pretreatment unit, solid fuel is supplied to spray bio-liquid onto the solid fuel, thereby impregnating the solid fuel with the bio-liquid; A heat treatment unit is provided to which the solid fuel impregnated with the biological liquid is supplied for heat treatment of the solid fuel impregnated with the biological liquid. A reheat steam supply unit supplies reheat steam to the heat treatment unit to directly heat the solid fuel supplied to the heat treatment unit; A cooling unit is provided to which the solid fuel, which has been heat-treated by the heat treatment unit, is supplied to cool the solid fuel; and A coolant supply unit supplies coolant to the cooling unit to cool the solid fuel supplied to the cooling unit. The biological fluid includes a liquid component containing glucose and xylose.

2. The solid fuel reheat steam processing system according to claim 1, wherein, The preprocessing unit includes: The first body, into which the solid fuel is supplied; A bio-liquid injection unit, disposed within the first body, for injecting the bio-liquid onto the solid fuel supplied to the first body; and A biological liquid supply unit, which is connected to the biological liquid injection unit to supply the biological liquid to the biological liquid injection unit.

3. The solid fuel reheat steam treatment system according to claim 2, wherein, The bio-liquid injection unit includes at least one bio-liquid injection pipe, which includes a plurality of first nozzles arranged along the length of the first body within the first body to inject the bio-liquid.

4. The solid fuel reheat steam treatment system according to claim 2, wherein, The first body includes a cylindrical rotary furnace rotating at a predetermined speed.

5. The solid fuel reheat steam treatment system according to claim 1, wherein, The heat treatment unit includes: The second body, into which the solid fuel impregnated with the bio-liquid is supplied; and A reheat steam injection unit is provided at the outlet of the second body to inject the reheat steam supplied from the reheat steam supply unit into the second body.

6. The solid fuel reheat steam processing system according to claim 5, wherein, The reheat steam injection unit includes: A reheat steam supply unit, the reheat steam supply unit including a plurality of reheat steam channels, each of the plurality of reheat steam channels being connected to a reheat steam nozzle at its end; Reheat steam injection plate, wherein the reheat steam nozzle is embedded in the reheat steam injection plate; and A reheat steam main nozzle is connected to the reheat steam channel and is formed at the central axis of the reheat steam injection plate.

7. The solid fuel reheat steam processing system according to claim 6, wherein, The reheat steam injection unit further includes: A reheat steam bending member, the reheat steam bending member being used to guide the reheat steam along the periphery of the end of the reheat steam injection plate toward the center of the second body; and A reheat steam turbulence generating member is formed between the reheat steam bending member and the end of the reheat steam injection plate to induce turbulence in the injected reheat steam.

8. The solid fuel reheat steam processing system according to claim 1, wherein, The cooling unit includes: The third body, into which the solid fuel, which has been heat-treated by the heat treatment unit, is supplied; A jacket, the jacket being disposed around the third body; and A coolant injection unit is disposed between the third body and the jacket to spray coolant onto the outer surface of the third body.

9. The solid fuel reheat steam processing system according to claim 8, wherein, The coolant injection unit includes at least one coolant injection pipe, which includes a plurality of second nozzles arranged along the length of the third body between the third body and the jacket to inject the coolant.

10. The solid fuel reheat steam processing system according to claim 8, wherein, The cooling unit also includes a water tank disposed below the jacket to store the coolant discharged through the outlet of the jacket, thereby circulating the coolant sprayed by the coolant injection unit to the coolant supply unit.

11. The solid fuel reheat steam processing system according to claim 1, further comprising: An impurity removal unit is configured to remove impurities contained in the steam discharged from the heat treatment unit. A blower unit configured to circulate the steam passing through the impurity removal unit to the reheat steam supply unit; as well as The discharge unit is configured to discharge steam through the blower unit in the same amount as the steam flow generated during the heat treatment of the solid fuel by the heat treatment unit.

12. The solid fuel reheat steam processing system according to claim 11, wherein, The impurity removal unit includes: At least one cyclone separator; and At least one bag filter, which is in communication with the cyclone separator.

13. The solid fuel reheat steam processing system according to claim 1, further comprising: A pulverizing unit configured to pulverize the solid fuel; A separation unit configured to separate solid fuels with an average particle size of less than 6 mm that have been pulverized by the crushing unit; as well as A storage unit configured to store the solid fuel separated by the separation unit. The solid fuel stored in the storage unit is supplied to the pretreatment unit.

14. The solid fuel reheat steam processing system according to claim 13, further comprising: A conveying unit is disposed between the storage unit and the pretreatment unit for conveying the solid fuel stored in the storage unit to the pretreatment unit.

15. The solid fuel reheat steam processing system according to claim 14, wherein, The conveying unit includes: A first screw feeder is configured to convey the solid fuel stored in the storage unit; The bucket, in which the solid fuel conveyed by the first screw feeder is contained; and A lift, wherein the bucket is connected to the lift to raise the bucket in the height direction, and The bucket is raised by the elevator, and the solid fuel contained in the raised bucket is supplied to the pretreatment unit.

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