Gasification ash drying, coarse grinding and combustion integrated system and method

Abstract

This invention provides an integrated system and method for drying, coarse grinding, and combustion of gasified ash, relating to the field of coal chemical gasification ash treatment technology. It includes a drying rotary kiln, a mill, a first dust collector, an insulated furnace, and a hot blast stove. The feed inlet of the drying rotary kiln is suitable for introducing wet gasified ash, the ash outlet of the drying rotary kiln is connected to the inlet of the mill, and the outlet of the mill is connected to the air inlet of the first dust collector. The ash powder outlet of the first dust collector is divided into two paths: one connected to the fuel inlet of the insulated furnace, and the other connected to the fuel inlet of the hot blast stove. The flue gas outlet of the hot blast stove is connected to the hot air inlet of the drying rotary kiln, so that high-temperature flue gas enters the drying rotary kiln to dry the wet gasified ash. This invention can utilize the heat generated by the combustion of the ash itself to dry and coarsely grind both coarse and fine ash, eliminating the need for additional heat and fine ash pressure filtration processes, achieving energy self-balance, reducing equipment investment, and lowering dehydration costs.

Description

Technical Field

[0001] This invention relates to the field of coal chemical gasification ash and slag treatment technology, and in particular to an integrated system and method for drying, coarse grinding and combustion of gasification ash and slag. Background Technology

[0002] Gasification ash is a solid residue discharged after the incomplete combustion / gasification of coal at high temperatures (1200-1500℃) in a gasifier. It belongs to the bulk solid waste of coal chemical industry and is divided into coarse ash and fine ash. Gasification ash has the potential for direct combustion, and the relevant direct incineration technologies include the following two:

[0003] 1. The co-firing of gasification fine slag with high-calorific-value fuels such as biomass and coal is usually done in circulating fluidized bed boilers. However, when co-firing high-moisture fine slag, the capacity of circulating fluidized bed boilers is insufficient, and there are problems of incomplete combustion. While pre-filtering and dewatering the fine slag can help increase the co-firing capacity and combustion efficiency, the investment in filter presses is large, and the operating costs, such as filter cloth wear and power consumption, are high. 2. The gasification slag is burned in its pure form. Before burning, the slag is pre-dehydrated, including physical dehydration (such as filter press, spiral drum) and high-temperature phase change dehydration of flue gas (drying rotary kiln). This reduces the total water content of the slag entering the furnace to 30% or even less than 10%. However, fluidized bed boilers that burn gasification slag in their pure form are large and the heating surfaces need to be treated to prevent wear. SCR catalysts cannot prevent wear and are also prone to wear and failure. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, one embodiment of the present invention proposes an integrated system for drying, coarse grinding, and combustion of gasified ash residue. This integrated system can utilize the heat generated by the combustion of the ash residue itself to dry and coarsely grind the coarse and fine residue without the need for additional heat or fine residue pressure filtration process, thus achieving energy self-balance, reducing equipment investment, and lowering dewatering costs.

[0006] Another embodiment of the present invention proposes an integrated method for drying, coarse grinding, and combustion of gasified ash residue.

[0007] An integrated system for drying, coarse grinding, and combustion of gasified ash slag according to an embodiment of the present invention includes a drying rotary kiln, a mill, a first dust collector, an insulated furnace, and a hot air furnace. The feed inlet of the drying rotary kiln is adapted to allow the introduction of wet gasified ash slag. The slag outlet of the drying rotary kiln is connected to the inlet of the mill, and the outlet of the mill is connected to the air inlet of the first dust collector. The slag powder outlet of the first dust collector is divided into two paths: one path is connected to the fuel inlet of the insulated furnace, and the other path is connected to the fuel inlet of the hot air furnace. The flue gas outlet of the hot air furnace is connected to the hot air inlet of the drying rotary kiln, so that high-temperature flue gas enters the drying rotary kiln to dry the wet gasified ash slag.

[0008] According to an embodiment of the present invention, the integrated system for drying, coarse grinding, and combustion of gasified ash slag involves adding wet gasified ash slag into a drying rotary kiln for drying to obtain dry slag and high-humidity flue gas. The dry slag and high-humidity flue gas are then fed into a mill for coarse grinding of the dry slag. The coarsely ground ash slag is collected by a first dust collector to obtain dry slag powder. The dry slag powder is split, with one path sent to an adiabatic furnace for ignition and combustion, and the other path sent to a hot blast stove for combustion. The high-temperature flue gas generated in the hot blast stove is then sent to the drying rotary kiln to dry the wet gasified ash slag. The aforementioned process uses the high-temperature flue gas generated from the combustion of fine and coarse slag in the ash slag as the drying agent. The heat source achieves a self-sufficient closed-loop energy balance without external fuel, relying on the calorific value of the ash residue itself to achieve full energy self-sufficiency. This eliminates the need for expensive pressure filtration and natural gas / coal supplementary heating, reducing equipment investment and improving project economics. It solves the problem of direct incineration of fine and coarse ash residue, enabling the resource-based disposal of coal chemical solid waste. Therefore, compared with related technologies, this invention can utilize the heat generated by the combustion of the ash residue itself to dry and coarsely grind coarse and fine ash residue without additional heat or fine ash pressure filtration process, achieving energy self-balance, reducing equipment investment, and lowering dewatering costs.

[0009] In some specific embodiments, the drying rotary kiln is equipped with baffles and / or chains to break up the wet gasified ash slag inside the drying rotary kiln.

[0010] In some embodiments, the mass ratio of fine slag to coarse slag in the wet gasification ash is 5:5 to 3:7.

[0011] In some embodiments, the mill discharges a particle size of 200 mesh with a passing rate of more than 60%.

[0012] In some embodiments, the dry slag powder at the slag powder outlet of the first dust collector is diverted, wherein 30% to 40% of the dry slag powder enters the hot blast stove for combustion, and 60% to 70% of the dry slag powder enters the adiabatic furnace for combustion to produce steam as a byproduct.

[0013] In some embodiments, the system further includes a cyclone separator, which is provided between the flue gas outlet of the hot air furnace and the hot air inlet of the drying rotary kiln; The temperature of the high-temperature flue gas is 900℃~1100℃. Cold air is also introduced between the cyclone separator and the hot air inlet of the drying rotary kiln to mix with the high-temperature flue gas, thereby reducing the temperature of the high-temperature flue gas to 600℃~800℃. The cold air is cold air or low-temperature flue gas from the boiler.

[0014] In some embodiments, a first powder bin is provided between the slag and powder outlet of the first dust collector and the fuel inlet of the insulated furnace, and a second powder bin is provided between the slag and powder outlet of the first dust collector and the fuel inlet of the hot air furnace.

[0015] In some specific embodiments, the discharge port of the first powder silo is connected to the fuel inlet of the adiabatic furnace in sequence through the first intermediate silo and the first feeder. The air inlet of the first feeder is equipped with a primary air fan so that the slag powder enters the first feeder from the first powder silo through the first intermediate silo, and then the slag powder is sent into the adiabatic furnace for ignition and combustion by the conveying air provided by the primary air fan. The discharge port of the second powder silo is connected to the fuel inlet of the hot blast stove in sequence through the second intermediate silo and the second feeder. The air inlet of the second feeder is equipped with a primary air fan so that the slag powder enters the second feeder from the second powder silo through the second intermediate silo, and then is sent into the hot blast stove for combustion by the conveying air provided by the primary air fan.

[0016] In some embodiments, the flue gas outlet of the drying rotary kiln is connected to the inlet of the first dust collector via a bypass pipe, so that the first dust collector collects the fine slag in the flue gas. This ensures full recovery of fine slag and minimizes energy consumption.

[0017] In some embodiments, the system further includes a desulfurization tower, wherein the flue gas outlet of the first dust collector is connected to the inlet of the desulfurization tower so that low-temperature, high-humidity flue gas enters the desulfurization tower for desulfurization; A first induced draft fan is provided between the flue gas outlet of the first dust collector and the air inlet of the desulfurization tower.

[0018] In some embodiments, the insulated furnace includes a furnace body, a burner, a high-temperature economizer, a low-temperature economizer, a two-stage air preheater, and an SCR denitrification unit. The furnace body has a furnace chamber, and the burner is provided with a fuel inlet for the insulated furnace. The burner is connected to the furnace chamber to inject dry slag powder fuel into the furnace chamber. The high-temperature economizer, the low-temperature economizer, and the two-stage air preheater are connected in sequence. The inlet of the high-temperature economizer is connected to the flue gas outlet of the furnace chamber, and the outlet of the two-stage air preheater is connected to the air inlet of the desulfurization tower. The secondary air in the burner and the tertiary air in the furnace chamber can both be preheated by the two-stage air preheater. The SCR denitrification unit is located between the high-temperature economizer and the low-temperature economizer to denitrify the flue gas.

[0019] In some specific embodiments, the insulated furnace further includes a steam drum, in which high-temperature flue gas in the furnace enters the heating surface to exchange heat with the heat exchange tube bundle, and a steam-water mixture (i.e., water + saturated steam) is generated in the heat exchange tube bundle. The steam-water mixture enters the steam drum so that water and steam are separated by the steam drum, thereby realizing the production of steam from ash incineration.

[0020] In some embodiments, the system further includes a second dust collector and an ash silo. The second dust collector is provided between the outlet of the two-stage air preheater and the inlet of the desulfurization tower. That is, the inlet of the second dust collector is connected to the outlet of the two-stage air preheater, and the flue gas outlet of the second dust collector is connected to the inlet of the desulfurization tower. The ash silo is connected to the ash outlet of the second dust collector to collect furnace ash.

[0021] In some specific embodiments, a second induced draft fan is provided between the flue gas outlet of the second dust collector and the air inlet of the desulfurization tower.

[0022] In some embodiments, the insulated furnace further includes an external secondary air fan, the inlet of which is connected to both the external environment and the flue gas outlet of the second dust collector, and the outlet of which is connected to the external secondary air inlet of the burner to supply external secondary air to the burner.

[0023] According to an embodiment of the present invention, a method for integrated drying, coarse grinding, and combustion of gasified ash residue, based on the integrated drying, coarse grinding, and combustion system for gasified ash residue described in any of the preceding embodiments, includes the following steps: Drying involves passing the wet gasified ash slag into a drying rotary kiln to dry it, thus obtaining dry slag. Coarse grinding allows the dry slag and the high-humidity flue gas to enter the mill, where the mill coarsely grinds the dry slag to obtain coarsely ground ash slag. The ash slag is collected by the first dust collector to obtain dry slag powder. In the incineration process, the dry slag powder is divided into two streams. One stream is sent to an insulated furnace for ignition and combustion, and the other stream is sent to a hot blast furnace for combustion. The high-temperature flue gas in the hot blast furnace enters the drying rotary kiln to dry the wet gasified ash slag, resulting in high-humidity flue gas and the dry slag.

[0024] The technical advantages of the integrated method for drying, coarse grinding, and combustion of gasified ash slag according to the embodiments of the present invention are the same as those of the integrated system for drying, coarse grinding, and combustion of gasified ash slag described above, and will not be repeated here.

[0025] In some embodiments, the method further includes the step of: For desulfurization, the high-humidity flue gas passes sequentially through the mill and the first dust collector to obtain low-temperature high-humidity flue gas. At the same time, the high-temperature flue gas in the adiabatic furnace passes sequentially through a high-temperature economizer, an SCR denitrification unit, a low-temperature economizer, a two-stage air preheater, and a second dust collector to obtain low-temperature flue gas. Both the low-temperature high-humidity flue gas and the low-temperature flue gas are sent to the desulfurization tower for desulfurization.

[0026] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the integrated system for drying, coarse grinding, and combustion of gasified ash slag according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic flowchart of the integrated method for drying, coarse grinding, and combustion of gasified ash slag according to an embodiment of the present invention.

[0029] Figure label: 1. Drying rotary kiln; 11. Bypass pipe; 2. Grinding mill; 3. First dust collector; 31. First induced draft fan; 4. Insulated furnace; 41. Furnace body; 411. Furnace chamber; 42. Burner; 43. High-temperature economizer; 44. Low-temperature economizer; 45. Two-stage air preheater; 46. SCR denitrification unit; 47. Internal secondary air fan; 48. Tertiary air fan; 49. Steam drum; 491. External secondary air fan; 5. Hot air furnace; 51. Blower; 6. Cyclone separator; 7. First powder silo; 71. First intermediate silo; 72. First feeder; 8. Second powder silo; 81. Second intermediate silo; 82. Second feeder; 9. Desulfurization tower; 91. Second dust collector; 92. Ash silo; 93. Second induced draft fan. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] It should be noted that gasification ash, as a major solid waste in the coal chemical industry, faces the common problem of large-scale disposal that urgently needs to be solved. Among the relevant technologies, the fine gasification ash has a small particle size and is easily separated, requiring specialized structural design for the furnace and cyclone separator, such as lining the furnace with heat-insulating refractory mud and increasing the furnace height. Some researchers have even set up an insulated combustion chamber after the cyclone separator to ensure the complete combustion of small fine ash particles, resulting in high investment and operating costs. In addition, the coarse ash yield of fluidized bed gasifiers is often 1.5 to 2 times that of fine ash. The coarse ash from coal-water slurry gasifiers has a water content of 30% to 40% and an air-dried calorific value of 2000 to 2400 kcal / kg, which also has the value of combustion utilization. However, there are currently few schemes for the direct incineration of coarse ash. Therefore, the aforementioned technical problems have limited the resource utilization of gasification ash in coal chemical solid waste.

[0032] like Figure 1 As shown in the figure, an integrated system for drying, coarse grinding, and combustion of gasified ash slag according to an embodiment of the present invention includes a drying rotary kiln 1, a mill 2, a first dust collector 3, an insulated furnace 4, and a hot air furnace 5. The feed inlet of the drying rotary kiln 1 is suitable for introducing wet gasified ash slag. The slag outlet of the drying rotary kiln 1 is connected to the inlet of the mill 2, and the outlet of the mill 2 is connected to the air inlet of the first dust collector 3. The slag powder outlet of the first dust collector 3 is divided into two paths, one path is connected to the fuel inlet of the insulated furnace 4, and the other path is connected to the fuel inlet of the hot air furnace 5. The flue gas outlet of the hot air furnace 5 is connected to the hot air inlet of the drying rotary kiln 1, so that high-temperature flue gas enters the drying rotary kiln 1 to dry the wet gasified ash slag.

[0033] According to an embodiment of the present invention, the integrated system for drying, coarse grinding, and combustion of gasified ash slag involves adding wet gasified ash slag into a drying rotary kiln 1 for drying to obtain dry slag and high-humidity flue gas. The dry slag and high-humidity flue gas are then fed into a mill 2 for coarse grinding of the dry slag. The coarsely ground ash slag is collected by a first dust collector 3 to obtain dry slag powder. The dry slag powder is split, with one path sent to an insulated furnace 4 for ignition and combustion, and the other path sent to a hot blast stove 5 for combustion. The high-temperature flue gas generated in the hot blast stove 5 is then sent back to the drying rotary kiln 1 to dry the wet gasified ash slag. The aforementioned process utilizes the high-temperature flue gas generated from the combustion of fine and coarse slag in the ash slag as... This invention utilizes the heat generated by the combustion of ash to dry and coarse ash, achieving a self-sufficient closed-loop energy balance without external fuel. It achieves full energy self-sufficiency by relying on the calorific value of the ash itself, eliminating the need for expensive pressure filtration and natural gas / coal supplementary heating. This reduces equipment investment, improves project economics, and solves the problem of direct incineration of fine and coarse ash. It enables the resource-based treatment of coal chemical solid waste. Therefore, compared to related technologies, this invention can utilize the heat generated by the combustion of ash itself to dry and coarsely grind both coarse and fine ash without additional heat or fine ash pressure filtration, achieving energy self-balance, reducing equipment investment, and lowering dehydration costs.

[0034] It is understood that the present invention forms an integrated drying-combustion coupling system, in which the drying section and the incineration section are interdependent. The hot blast stove 5 is fed by slag powder, the drying process consumes the flue gas of the hot blast stove 5, and the remaining slag powder generates steam. The two processes are linked and the energy is in a closed loop. The drying and combustion units can be independently controlled.

[0035] Specifically, the wet gasification ash can be coal-water slurry gasification ash. The coarse / fine ash in coal-water slurry gasification ash has a high calorific value (coarse ash approximately 2000~2400 kcal / kg) and sufficient residual carbon, providing stable combustion conditions. Therefore, a combustion steam generation route is designed, with the fine ash having an initial moisture content of 62.3% and the coarse ash 33.7%. The coarse ash in the wet gasification ash is screened to remove the glassy substance. The wet gasification ash and high-temperature flue gas undergo co-current or counter-current heat exchange in the drying rotary kiln 1 to reduce the moisture content of the wet gasification ash to below 10%, and then enter the mill 2 together with the high-humidity flue gas. The first dust collector 3 can be a bag filter. A blower 51 is installed at the air inlet of the hot blast stove 5 to blow external air into the hot blast stove 5 for combustion.

[0036] In some specific embodiments, the drying rotary kiln 1 is equipped with baffles and / or iron chains to break up the wet gasified ash slag inside the drying rotary kiln 1, thereby improving the ash slag drying efficiency.

[0037] like Figure 1 As shown, in some embodiments, the mass ratio of fine slag to coarse slag in wet gasification ash is 5:5 to 3:7, so as to match the coarse and fine slag output of conventional gasifiers, thereby facilitating the resource-based disposal of coal chemical solid waste.

[0038] like Figure 1 As shown, in some embodiments, the discharge particle size of mill 2 is 200 mesh with a passing rate of more than 60%. That is to say, when the material is screened with a standard sieve of 200 mesh, the mass of particles that can pass through the sieve accounts for more than 60% of the total mass of the material. Therefore, the present invention does not require fine powder classification. The particle size of the ash slag after coarse grinding by mill 2 can meet the subsequent combustion requirements, simplifying the construction of the entire system.

[0039] like Figure 1 As shown, in some embodiments, the dry slag powder at the outlet of the first dust collector 3 is diverted, with 30% to 40% of the dry slag powder entering the hot blast stove 5 for combustion and 60% to 70% entering the insulated furnace 4 for combustion to produce steam as a byproduct. In other words, the dry slag powder diversion of the present invention involves 30% to 40% being sent to an independent hot blast stove 5 for combustion to produce flue gas specifically for drying, while 60% to 70% being sent to an insulated swirl furnace 411 for combustion to produce industrial steam. The two combustion devices, the hot blast stove 5 and the steam-producing furnace 411, are independent of each other, which can realize the on-site incineration of ash and slag.

[0040] like Figure 1As shown, in some embodiments, the system also includes a cyclone separator 6. A cyclone separator 6 is provided between the flue gas outlet of the hot blast stove 5 and the hot air inlet of the drying rotary kiln 1. The cyclone separator 6 is used to perform gas-solid separation on the high-temperature flue gas, that is, to filter out the furnace ash in the high-temperature flue gas, so as to reduce the impact of furnace ash entering the drying rotary kiln 1 on the working performance of the drying rotary kiln 1.

[0041] The temperature of the high-temperature flue gas is 900℃~1100℃. Cold air is also introduced between the hot air inlet of the cyclone separator 6 and the drying rotary kiln 1 to mix with the high-temperature flue gas, thereby reducing the temperature of the high-temperature flue gas to 600℃~800℃. This ensures that the temperature of the flue gas entering the drying rotary kiln 1 meets the drying requirements, avoids the impact of excessively high temperature on the wet gasification ash slag inside the drying rotary kiln 1, and ensures the safety of the drying process. The cold air is either cold air or low-temperature flue gas from the boiler.

[0042] Specifically, the flue gas outlet of the hot blast furnace 5 is connected to the air inlet of the cyclone separator 6, the flue gas outlet of the cyclone separator 6 is connected to the hot air inlet of the drying rotary kiln 1, and cold air is introduced between the two to reduce the temperature of the high-temperature flue gas. The ash outlet of the cyclone separator 6 can discharge ash.

[0043] like Figure 1 As shown, in some embodiments, a first powder bin 7 is provided between the slag powder outlet of the first dust collector 3 and the fuel inlet of the adiabatic furnace 4, and a second powder bin 8 is provided between the slag powder outlet of the first dust collector 3 and the fuel inlet of the hot air furnace 5.

[0044] It is understandable that the first powder silo 7 and the second powder silo 8 can store dry slag powder, which is conducive to ensuring the batch and continuous treatment of wet gasification ash slag (or coal chemical solid waste).

[0045] In some specific embodiments, the discharge port of the first powder silo 7 is connected to the fuel inlet of the adiabatic furnace 4 in sequence through the first intermediate silo 71 and the first feeder 72. The air inlet of the first feeder 72 is equipped with a primary air fan so that the slag powder enters the first feeder 72 from the first powder silo 7 via the first intermediate silo 71, and then the slag powder is sent into the adiabatic furnace 4 for ignition and combustion by the conveying air provided by the primary air fan.

[0046] The discharge port of the second powder silo 8 is connected to the fuel inlet of the hot blast stove 5 in sequence through the second intermediate silo 81 and the second feeder 82. The air inlet of the second feeder 82 is equipped with a primary air fan so that the slag powder enters the second feeder 82 from the second powder silo 8 through the second intermediate silo 81, and then the slag powder is sent into the hot blast stove 5 for combustion by the conveying air provided by the primary air fan.

[0047] like Figure 1As shown, in some embodiments, the flue gas outlet of the drying rotary kiln 1 is connected to the air inlet of the first dust collector 3 through a bypass pipe 11, so that the first dust collector 3 can collect the fine slag in the flue gas. That is, some of the dry fine slag is collected by the first dust collector 3 and sent to the first powder bin 7 or the second powder bin 8, while the remaining dry ash slag enters the mill 2 for grinding, so as to ensure full recovery of fine slag and environmental protection and energy consumption.

[0048] Specifically, the flue gas temperature at the outlet of the drying rotary kiln 1 is 110℃~150℃.

[0049] like Figure 1 As shown, in some embodiments, the system further includes a desulfurization tower 9, and the flue gas outlet of the first dust collector 3 is connected to the air inlet of the desulfurization tower 9 so that low-temperature and high-humidity flue gas enters the desulfurization tower 9 for desulfurization.

[0050] A first induced draft fan 31 is installed between the flue gas outlet of the first dust collector 3 and the air inlet of the desulfurization tower 9, so that the low temperature and high humidity flue gas is introduced into the desulfurization tower 9 for desulfurization treatment, thereby reducing environmental pollution.

[0051] Specifically, the flue gas outlet of the desulfurization tower 9 is located at the top of the desulfurization tower 9 and connected to the chimney. The air inlet of the desulfurization tower 9 is located near the bottom of the desulfurization tower 9, and the desulfurizing agent inlet of the desulfurization tower 9 is located near the top of the desulfurization tower 9, so that the flow direction of the desulfurizing agent in the desulfurization tower 9 is opposite to the flow direction of the flue gas in the desulfurization tower 9, thus ensuring the desulfurization effect on the flue gas.

[0052] like Figure 1 As shown, in some embodiments, the insulated furnace 4 includes a furnace body 41, a burner 42, a high-temperature economizer 43, a low-temperature economizer 44, a two-stage air preheater 45, and an SCR denitrification unit 46. The furnace body 41 has a furnace chamber 411. The burner 42 is provided with a fuel inlet for the insulated furnace 4. The burner 42 is connected to the furnace chamber 411 to inject dry slag powder fuel into the furnace chamber 411. The high-temperature economizer 43, the low-temperature economizer 44, and the two-stage air preheater 45 are connected in sequence. The inlet of the high-temperature economizer 43 is connected to the flue gas outlet of the furnace chamber 411. The outlet of the two-stage air preheater 45 is connected to the air inlet of the desulfurization tower 9. The secondary air inside the burner 42 and the tertiary air in the furnace chamber 411 can both be preheated in the two-stage air preheater 45. The SCR denitrification unit 46 is located between the high-temperature economizer 43 and the low-temperature economizer 44 to denitrify the flue gas.

[0053] Understandably, the high-temperature economizer 43, the low-temperature economizer 44, and the two-stage air preheater 45 work together to form the tail-end waste heat exchange system of the adiabatic furnace 4. This system can preheat the secondary and tertiary air by recovering the heat from the flue gas, thus realizing the utilization of waste heat from the flue gas. Meanwhile, the SCR denitrification unit 46 can remove NOx from the flue gas, which, in conjunction with the subsequent desulfurization tower 9, can further ensure the quality of flue gas emissions and reduce environmental pollution.

[0054] Specifically, the burner 42 is located at the top of the furnace body 41, and the burner 42 can be a swirl burner 42. The adiabatic furnace 4 also includes an internal secondary air fan 47 and a tertiary air fan 48. The inlet of each of the internal secondary air fan 47 and the tertiary air fan 48 is connected to the external environment. The outlet of the internal secondary air fan 47, the internal secondary air inlet of the two-stage air preheater 45 and the burner 42 are connected in sequence to blow internal secondary air into the burner 42. The outlet of the tertiary air fan 48, the internal secondary air inlet of the two-stage air preheater 45 and the furnace 411 are connected in sequence to blow tertiary air into the furnace 411. The hot side of the two-stage air preheater 45 is supplied with flue gas that has undergone heat exchange in the high-temperature economizer 43, denitrification (i.e., removal of nitrogen oxides) in the SCR denitrification unit 46, and heat exchange in the low-temperature economizer 44. The cold side of the two-stage air preheater 45 is supplied with air blown in by the internal secondary air fan 47 or the tertiary air fan 48 to achieve preheating of the internal secondary air and the tertiary air. The feed inlet of the first feeder 72 is connected to the outlet of the first intermediate silo 71, and the discharge outlet of the first feeder 72 is connected to the fuel inlet of the adiabatic furnace 4, so that the dry slag powder enters the burner 42 and mixes with its internal combustion air (including internal secondary air and external secondary air as described below) to form a combustible gas flow.

[0055] In some specific embodiments, the adiabatic furnace 4 also includes a steam drum 49. High-temperature flue gas in the furnace 411 enters the heating surface to exchange heat with the heat exchange tube bundle. A steam-water mixture (i.e., water + saturated steam) is generated in the heat exchange tube bundle. The steam-water mixture enters the steam drum 49 so that water and steam are separated by the steam drum 49, thereby realizing the production of steam from ash and slag incineration.

[0056] It should be noted that the combustion of fine slag is completed through the swirl burner 42 of the insulated furnace 4 coupled to the furnace chamber 4 (i.e., the furnace chamber 411 of the insulated furnace 4). The calorific value of the dried ash is required to be no less than 1000 kcal / kg, and the total water content <10%. The combustion air temperature is 100℃~500℃, and the heat load of the furnace chamber 4 cross-section is 1.5~2.0 MW / m². 2 The furnace 411 volumetric heat load is 80–150 kW / m³. 3 The fine slag incinerator is long and slender (because according to the formula qF=Q / F, a larger heat load means a smaller cross-sectional area of ​​the furnace 411 for the same incineration heat; however, according to the formula qV=Q / V for the volumetric heat load of the furnace 411, the ratio of the furnace 411's height to diameter to its length to height is large, so the furnace 411 is long and slender). High-temperature flue gas enters the heating surface to produce saturated steam or superheated steam. According to the needs of coal chemical plants, the steam pressure level can be 3.8 MPa, 2.5 MPa, and 1.6 MPa.

[0057] like Figure 1As shown, in some embodiments, the system further includes a second dust collector 91 and an ash silo 92. The second dust collector 91 is provided between the outlet of the two-stage air preheater 45 and the inlet of the desulfurization tower 9. That is, the inlet of the second dust collector 91 is connected to the outlet of the two-stage air preheater 45, and the flue gas outlet of the second dust collector 91 is connected to the inlet of the desulfurization tower 9. The ash silo 92 is connected to the ash outlet of the second dust collector 91 to collect furnace ash.

[0058] Understandably, the second dust collector 91 can filter out furnace ash in the low-temperature flue gas. Combined with the denitrification and desulfurization treatment of the flue gas in the above structure, the purification treatment of the flue gas can be further achieved.

[0059] In some specific embodiments, a second induced draft fan 93 is provided between the flue gas outlet of the second dust collector 91 and the air inlet of the desulfurization tower 9, so that the flue gas in the second dust collector 91 is introduced into the desulfurization tower 9 for desulfurization by the second induced draft fan 93, thereby ensuring the flue gas treatment efficiency.

[0060] like Figure 1 As shown, in some embodiments, the adiabatic furnace 4 also includes an external secondary air fan 491. The inlet of the external secondary air fan 491 is connected to the external environment and the flue gas outlet of the second dust collector 91. The outlet of the external secondary air fan 491 is connected to the external secondary air inlet of the burner 42 to supply external secondary air to the burner 42.

[0061] Understandably, the external secondary air fan 491 can introduce air or flue gas treated by the second dust collector 91 into the burner 42 to provide external secondary air to the burner 42, and the recirculation of flue gas can realize the recovery and reuse of combustible gas or unburned carbon particles in the flue gas to improve resource utilization.

[0062] like Figure 2 As shown, an integrated method for drying, coarse grinding, and combustion of gasified ash slag according to an embodiment of the present invention, based on the integrated system for drying, coarse grinding, and combustion of gasified ash slag of any of the above embodiments, includes the following steps: Step S1, drying: The wet gasified ash slag is passed into the drying rotary kiln 1 for drying to obtain dry slag; Step S2, coarse grinding, allows dry slag and high-humidity flue gas to enter mill 2. Mill 2 coarsely grinds the dry slag to obtain coarsely ground ash slag. The ash slag is collected by the first dust collector 3 to obtain dry slag powder. Step S3, incineration: The dry slag powder is divided into two streams. One stream is sent to the insulated furnace 4 for ignition and combustion, and the other stream is sent to the hot blast furnace 5 for combustion. The high-temperature flue gas in the hot blast furnace 5 enters the drying rotary kiln 1 to dry the wet gasified ash slag, resulting in high-moisture flue gas and dry slag.

[0063] The technical advantages of the integrated method for drying, coarse grinding, and combustion of gasified ash slag according to the embodiments of the present invention are the same as those of the integrated system for drying, coarse grinding, and combustion of gasified ash slag described above, and will not be repeated here.

[0064] like Figure 2 As shown, in some embodiments, the following steps are also included: In step S4, desulfurization, the high-humidity flue gas passes sequentially through mill 2 and the first dust collector 3 to obtain low-temperature high-humidity flue gas. At the same time, the high-temperature flue gas in the adiabatic furnace 4 passes sequentially through high-temperature economizer 43, SCR denitrification unit 46, low-temperature economizer 44, two-stage air preheater 45 and second dust collector 91 to obtain low-temperature flue gas. Both the low-temperature high-humidity flue gas and the low-temperature flue gas are sent to desulfurization tower 9 for desulfurization.

[0065] Example 1 Taking the gasification ash produced by a certain coal-water slurry gasifier as an example, Table 1 shows the composition of the gasification ash. The coal chemical plant produces 250,000 tons of fine gasification ash and 400,000 tons of coarse gasification ash annually.

[0066] Table 1. Composition of Gasification Slag

[0067] Using the integrated gasification ash drying, coarse grinding, and combustion system of this invention, energy calculations were performed on the fine ash. Considering drying efficiency, drying 1 kg of water requires 800 kcal of heat. The energy calculations are shown in Tables 2 and 3. The fine ash production is 250,000 tons, of which 41.71% is used for drying and the remaining 58.29% is used for incineration to produce steam, with a steam output of 209,000 tons. The coarse ash production is 400,000 tons, of which 14.67% is used for drying and the remaining 85.33% is used for incineration to produce steam, with a steam output of 631,000 tons.

[0068] Table 2 Energy Balance Table for Fine Slag

[0069] Table 3 Energy Balance Table for Coarse Slag

[0070] Therefore, compared with related technologies, the present invention dries and coarsely grinds coarse and fine slag to prepare powdered fuel, which has the following technical advantages: 1) This invention reduces dehydration costs by using the heat generated from the combustion of the ash residue itself as a drying heat source, eliminating the need for additional heat. 2) This invention mixes and coarsely grinds coarse and fine slag, resulting in a uniform particle size distribution of the material and improving the burnout rate of the ash slag; 3) This invention separates ash drying and ash combustion for steam generation. The hot air furnace 5 is used for drying, and the insulated furnace 4 is used for steam generation. The two are independent of each other, which improves the ease of system operation.

[0071] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0073] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0074] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0075] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0076] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An integrated system for drying, coarse grinding, and combustion of gasified ash residue, characterized in that, include: The equipment includes a drying rotary kiln, a mill, and a first dust collector. The feed inlet of the drying rotary kiln is adapted to allow the introduction of wet gasified ash slag. The slag outlet of the drying rotary kiln is connected to the inlet of the mill, and the outlet of the mill is connected to the air inlet of the first dust collector. The insulated furnace and the hot air furnace are provided. The slag powder outlet of the first dust collector is divided into two paths. One path is connected to the fuel inlet of the insulated furnace, and the other path is connected to the fuel inlet of the hot air furnace. The flue gas outlet of the hot air furnace is connected to the hot air inlet of the drying rotary kiln, so that the high-temperature flue gas enters the drying rotary kiln to dry the wet gasified ash slag.

2. The integrated system for drying, coarse grinding, and combustion of gasified ash slag according to claim 1, characterized in that, The mass ratio of fine slag to coarse slag in the wet gasification ash residue is 5:5 to 3:7; and / or, The mill discharges a 200-mesh particle size with a passing rate greater than 60%; and / or, The dry slag powder at the outlet of the first dust collector is diverted, wherein 30% to 40% of the dry slag powder enters the hot blast stove for combustion, and 60% to 70% of the dry slag powder enters the adiabatic furnace for combustion to produce steam as a byproduct.

3. The integrated system for drying, coarse grinding, and combustion of gasified ash slag according to claim 1, characterized in that, It also includes a cyclone separator, which is provided between the flue gas outlet of the hot air furnace and the hot air inlet of the drying rotary kiln; The temperature of the high-temperature flue gas is 900℃~1100℃. Cold air is also introduced between the cyclone separator and the hot air inlet of the drying rotary kiln to mix with the high-temperature flue gas, thereby reducing the temperature of the high-temperature flue gas to 600℃~800℃. The cold air is cold air or low-temperature flue gas from the boiler.

4. The integrated system for drying, coarse grinding, and combustion of gasified ash slag according to claim 1, characterized in that, A first powder bin is provided between the slag powder outlet of the first dust collector and the fuel inlet of the insulated furnace, and a second powder bin is provided between the slag powder outlet of the first dust collector and the fuel inlet of the hot air furnace.

5. The integrated system for drying, coarse grinding, and combustion of gasified ash slag according to claim 1, characterized in that, The flue gas outlet of the drying rotary kiln is connected to the inlet of the first dust collector via a bypass pipe, so that the first dust collector can collect the fine slag in the flue gas.

6. The integrated system for drying, coarse grinding, and combustion of gasified ash slag according to any one of claims 1-5, characterized in that, It also includes a desulfurization tower, wherein the flue gas outlet of the first dust collector is connected to the air inlet of the desulfurization tower so that low-temperature and high-humidity flue gas enters the desulfurization tower for desulfurization; A first induced draft fan is provided between the flue gas outlet of the first dust collector and the air inlet of the desulfurization tower.

7. The integrated system for drying, coarse grinding, and combustion of gasified ash slag according to claim 6, characterized in that, The insulated furnace includes: The furnace body has a furnace chamber, and the burner is provided with a fuel inlet for the insulated furnace. The burner is connected to the furnace chamber to inject dry slag powder fuel into the furnace chamber. A high-temperature economizer, a low-temperature economizer, and a two-stage air preheater are connected in sequence. The inlet of the high-temperature economizer is connected to the flue gas outlet of the furnace, and the outlet of the two-stage air preheater is connected to the air inlet of the desulfurization tower. The secondary air inside the burner and the tertiary air in the furnace can both be preheated in the two-stage air preheater. The SCR denitrification unit is located between the high-temperature economizer and the low-temperature economizer to denitrify the flue gas.

8. The integrated system for drying, coarse grinding, and combustion of gasified ash slag according to claim 7, characterized in that, Also includes: The second dust collector is provided between the outlet of the two-stage air preheater and the inlet of the desulfurization tower; An ash silo is connected to the ash outlet of the second dust collector to collect furnace ash.

9. The integrated system for drying, coarse grinding, and combustion of gasified ash slag according to claim 8, characterized in that, The insulated furnace also includes an external secondary air fan. The inlet of the external secondary air fan is connected to both the external environment and the flue gas outlet of the second dust collector. The outlet of the external secondary air fan is connected to the external secondary air inlet of the burner to supply external secondary air to the burner.

10. A method for integrating drying, coarse grinding, and combustion of gasified ash, based on the integrated system for drying, coarse grinding, and combustion of gasified ash as described in any one of claims 1-9, characterized in that, The method includes the following steps: Drying involves passing the wet gasified ash slag into a drying rotary kiln to dry it, thus obtaining dry slag. Coarse grinding allows the dry slag and the high-humidity flue gas to enter the mill, where the mill coarsely grinds the dry slag to obtain coarsely ground ash slag. The ash slag is collected by the first dust collector to obtain dry slag powder. In the incineration process, the dry slag powder is divided into two streams. One stream is sent to an insulated furnace for ignition and combustion, and the other stream is sent to a hot blast furnace for combustion. The high-temperature flue gas in the hot blast furnace enters the drying rotary kiln to dry the wet gasified ash slag, resulting in high-humidity flue gas and the dry slag.

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