Drying incineration system and drying incineration method suitable for high-water-content gasified fine slag

Abstract

The invention provides a drying incineration system and method suitable for high-water-content gasified fine slag, and belongs to the technical field of solid waste treatment. The drying incineration system comprises a carbon circulation system composed of a boiling bed and an incineration device. The fluidized bed is provided with a feeding port for high-water-content gasified fine slag to enter, an ash material inlet for receiving high-temperature circulating ash, a discharging port for discharging a water-containing material, a main material outlet for discharging first dried fine slag, and a fluidized bed hearth for drying the high-water-content gasified fine slag by the high-temperature circulating ash; the incinerator is used for incinerating the dried fine slag, the incinerator is provided with a first material returning opening connected with the main material outlet and a gas-phase material outlet located in the top of the incinerator and used for discharging gas-phase materials, and the gas-phase materials comprise flue gas and high-temperature circulating ash; the water content in the high-water-content gasified fine slag is greater than or equal to 60%, and the temperature of the high-temperature circulating ash is 1000-1200 DEG C.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste treatment, and in particular relates to a drying and incineration system and a drying and incineration method suitable for high-water-content gasified fine slag. Background Art

[0002] A large amount of high-water content gasification fine slag (water content greater than 60%) is produced during the coal gasification process. If these gasification fine slags are not properly handled, they will not only occupy a large amount of land resources, but also may pollute the soil, water and atmospheric environment. Traditional solid waste treatment methods have many problems in treating high-water content gasification fine slags. For example, when using steam indirect drying, there are problems such as low drying efficiency, high energy consumption, insufficient utilization of residual carbon and high treatment costs. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a drying and incineration system and a drying and incineration method suitable for high-water-content gasified fine slag, in order to at least partially solve the above technical problems. In this regard, the technical solution provided by the present invention is as follows.

[0004] In the first aspect of the present invention, a drying and incineration system suitable for high-water-content gasified fine slag is provided, comprising: a carbon circulation system consisting of a fluidized bed and an incineration device. The fluidized bed is provided with a feed port for high-water-content gasified fine slag, an ash material inlet for receiving high-temperature circulating ash, a discharge port for discharging water-containing materials, a main material outlet for discharging the first dried fine slag, and a fluidized bed furnace for high-temperature circulating ash to dry the high-water-content gasified fine slag; the incineration device comprises an incinerator for incinerating the dried fine slag entering the incinerator furnace, the incinerator is provided with a first return port connected to the main material outlet, and a gaseous material outlet located at the top of the incinerator for discharging gaseous materials, the gaseous materials comprising: flue gas and high-temperature circulating ash; the moisture content of the high-water-content gasified fine slag is ≥60%, and the temperature of the high-temperature circulating ash is 1000-1200℃.

[0005] As a second aspect of the present invention, a drying and incineration method suitable for high-water-content gasified fine slag is provided, which is performed by the above-mentioned drying and incineration system suitable for high-water-content gasified fine slag. The drying and incineration method comprises: drying the high-water-content gasified fine slag using high-temperature circulating ash in a fluidized bed to obtain first dried fine slag and water-containing material; incinerating the first dried fine slag in an incinerator to produce bottom ash and gaseous material, wherein the gaseous material comprises flue gas and high-temperature circulating ash.

[0006] Based on the above technical solution, the drying and incineration system and the drying and incineration method for high-water-content gasified fine slag provided by the present invention have at least one of the following beneficial effects:

[0007] (1) The present invention designs the structure of the fluidized bed and the incineration device, and introduces the high-temperature circulating ash and the high-water-content gasified fine slag into the fluidized bed. The high-temperature circulating ash and the high-water-content gasified fine slag are directly mixed and contacted, and the heat of the high-temperature circulating ash is transferred to the high-water-content gasified fine slag, so that the moisture on the surface of the high-water-content gasified fine slag evaporates quickly, thereby achieving efficient drying of the high-water-content gasified fine slag. Under the action of high temperature, the residual carbon wrapped in the ash in the high-water-content gasified fine slag is broken under the action of thermal stress, which increases the contact area between the residual carbon in the dried fine slag and oxygen, providing favorable conditions for subsequent combustion.

[0008] (2) The present invention combines the incineration device with the fluidized bed to realize the recycling of high-temperature circulating ash and heat, saving resources while making full use of waste. In the present invention, the circulating ash not only serves as a drying heat source for the high-water content gasified fine slag, but also continuously participates in the circulation of materials in the system, reducing additional energy consumption and material input. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic structural diagram of a drying and incineration system suitable for high-water-content gasified fine slag in an embodiment of the present invention.

[0010] [Description of Reference Numerals]

[0011] 1-fluidized bed, 11-feeding port, 12-ash material inlet, 13-discharge port, 14-main material outlet, 15-carrier gas inlet;

[0012] 2-incinerator, 21-first return port, 22-gas phase material outlet, 23-second return port, 24-primary air inlet, 25-secondary air inlet, 26-bed material inlet, 27-third return port, 28-slag discharge port;

[0013] 3-second gas-solid separator, 31-gas phase material inlet, 32-second exhaust port, 33-second solid material outlet;

[0014] 4-returner, 41-second solid material inlet, 42-first return material outlet, 43-second return material outlet;

[0015] 5-first gas-solid separator, 51 feed inlet, 52-first exhaust port, 53 first solid material outlet;

[0016] 6-condenser, 61-air inlet, 62-carrier gas outlet, 63-drain outlet;

[0017] 7- flue, 8- purification unit, 9- chimney;

[0018] A-high-water-content gasification fine slag, B-high-temperature circulating ash, C-water-containing material, D-first drying fine slag, E-water-containing circulating gas, F-second drying fine slag, G-primary air, H-secondary air, I-bed material, J-gas phase material, K-flue gas, L-circulating gas, M-condensed water, N-bottom ash. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0020] For gasified fine slag with high water content, traditional indirect drying or low-temperature drying methods are used. However, due to the low heat transfer efficiency, the drying process takes a long time and consumes a lot of energy, making it difficult to meet the needs of large-scale processing. For example, the use of some hot air drying equipment cannot quickly evaporate the water in the gasified fine slag with high water content, and there is also the problem of low processing efficiency. In addition, the gasified fine slag with high water content contains a certain amount of residual carbon. The current treatment technology (such as direct landfill or incineration) fails to effectively utilize this residual carbon, resulting in energy waste. In addition, the overall processing cost of comprehensive drying, incineration and subsequent pollutant treatment is high, and the treatment process is also relatively cumbersome.

[0021] In view of the current problems, the present invention provides a drying and incineration system and a drying and incineration method suitable for high-water-content gasified fine slag. The fluidized bed and the incineration device are combined through structural design, and the high-temperature circulating ash generated by the incineration device is used as a drying heat source to dry the high-water-content gasified fine slag entering the fluidized bed, and activate the residual carbon at the same time, so that the residual carbon in the high-water-content gasified fine slag is effectively utilized. In addition, by dynamically regulating the return material (first dried fine slag), the stable combustion of the first dried fine slag and lower pollutant emissions are achieved.

[0022] Specifically, as a first aspect of the present invention, a drying and incineration system suitable for gasified fine slag with high water content is provided, comprising: a carbon circulation system consisting of a fluidized bed and an incineration device.

[0023] Figure 1 It is a schematic structural diagram of a drying and incineration system suitable for high-water-content gasified fine slag in an embodiment of the present invention.

[0024] like Figure 1As shown, the fluidized bed 1 is provided with a feed port 11 for high-water gasified fine slag A, an ash material inlet 12 for receiving high-temperature circulating ash B, a discharge port 13 for discharging water-containing material C, a main material outlet 14 for discharging the first dried fine slag D, and a fluidized bed furnace for high-temperature circulating ash B to dry the high-water gasified fine slag A. The incineration device includes an incinerator 2 for incinerating the dried fine slag entering the furnace of the incinerator 2. The incinerator 2 is provided with a first return port 21 connected to the main material outlet 14, and a gaseous material outlet 22 located at the top of the incinerator 2 for discharging gaseous material J. The gaseous material J includes: flue gas K and high-temperature circulating ash B; wherein the water content of the high-water gasified fine slag A is ≥60%, and the temperature of the high-temperature circulating ash B is 1000-1200℃.

[0025] In the drying and incineration system of the present invention, the structures of the fluidized bed 1 and the incineration device are designed, and the high-temperature circulating ash B generated by the incineration device is introduced into the fluidized bed 1 and mixed with the high-water-content gasified fine slag A entering the fluidized bed 1. The heat of the high-temperature circulating ash B is used to quickly evaporate the moisture on the surface of the high-water-content gasified fine slag A, so as to achieve rapid drying and obtain the dried fine slag. At the same time, under the action of high temperature, the residual carbon wrapped in the ash in the high-water-content gasified fine slag A is broken under the action of thermal stress, which increases the contact area between the residual carbon in the dried fine slag and oxygen, so that the dried fine slag can be fully burned in the high-temperature environment (1000°C) of the incinerator 2, and the residual carbon energy in the dried fine slag is efficiently utilized.

[0026] Continue as Figure 1 As shown, the drying incineration system of the present invention further includes: a flue gas circulation system consisting of a first gas-solid separator 5 and a condenser 6 , wherein the carbon circulation system and the flue gas circulation system are coupled via a fluidized bed 1 .

[0027] Specifically, the first gas-solid separator 5 is located downstream of the fluidized bed 1, and is used to perform gas-solid separation on the water-containing material C to obtain the water-containing circulating gas E and the second dried fine slag F, wherein the first gas-solid separator 5 is provided with a feed port 51 connected to the discharge port 13, a first exhaust port 52 for discharging the water-containing circulating gas E, and a first solid material outlet 53 for discharging the second dried fine slag F. The condenser 6 is provided with an air inlet 61 connected to the first exhaust port 52, a drain port 63 for discharging condensed water M, and a carrier gas outlet 62 for discharging the circulating gas L.

[0028] In the fluidized bed 1, the highly water-containing gasified fine slag A is rapidly dried under the high temperature of the high-temperature circulating ash B to obtain the first dried fine slag D and the water-containing material C. Among them, the first dried fine slag D leaves the fluidized bed 1 through the main material outlet 14, and is returned to the incinerator 2 through the first return port 21 for incineration. By connecting the fluidized bed 1 and the first gas-solid separator 5, the first gas-solid separator 5 is used to perform gas-solid separation on the water-containing material C to obtain water-containing circulating gas E and the second dried fine slag F. The second dried fine slag F can be returned to the incinerator 2 for incineration, so as to realize the energy utilization of the residual carbon in the second dried fine slag F and reduce the waste of resources. Therefore, the dried fine slag entering the incinerator 2 includes the first dried fine slag D and / or the second dried fine slag F, the first dried fine slag D includes the first dried gas slag and part of the circulating ash, and the second dried fine slag F includes the second dried gas slag and part of the circulating ash. The first dried gas slag and the second dried gas slag have the same composition and only differ in density, wherein the density of the first dried gas slag is greater than the density of the second dried gas slag. Further, the water-containing circulating gas E enters the condenser 6, and the water vapor and circulating gas L in the water-containing circulating gas E are separated by the condensation of the condenser 6 to obtain the circulating gas L and condensed water M condensed from the water vapor, wherein the circulating gas L includes flue gas, carbon dioxide (CO2) and nitrogen (N2). The circulating gas L can be used as a carrier gas for the fluidized bed 1. Passing the circulating gas L into the fluidized bed 1 can maintain stable operation while reducing the use of additional carrier gas.

[0029] Therefore, continue as Figure 1As shown, the fluidized bed 1 is also provided with a carrier gas inlet 15 connected to the carrier gas outlet 62; the incinerator 2 is also provided with a second return port 23 connected to the first solid material outlet 53. Furthermore, the incinerator 2 is also provided with a primary air inlet 24 for primary air G to enter and a slag discharge port 28 for discharging bottom slag N located at the bottom of the furnace of the incinerator 2, as well as a secondary air inlet 25 for secondary air H to enter and a bed material inlet 26 for bed material I to enter located in the dense phase area of ​​the incinerator 2. The gaseous material J and the bottom slag N are formed by the incineration of dried fine slag. More specifically, the gaseous material J and the bottom slag N are formed by the incineration of dried fine slag in the presence of primary air G and / or secondary air H, wherein the primary air G and the secondary air H are any one of air and oxygen-enriched air, and the bed material I is quartz sand. Furthermore, the bed material inlet 26 is located upstream of the secondary air inlet 25, the secondary air inlet 25 is located in the dense phase area of ​​the incinerator 2, and there are one or more secondary air inlets 25, and the multiple secondary air inlets 25 are arranged in layers, and the spacing between layers is 0.5m-1.5m. Furthermore, multiple symmetrically arranged secondary air inlets 25 are arranged on the same horizontal plane, and the secondary air inlet 25 is located above the first return material port 21, the second return material port 23, and the third return material port 27; downward along the secondary air inlet 25, the third return material port 27, the first return material port 21, and the second return material port 23 are arranged in sequence. An air distribution unit is also provided at the bottom of the incinerator 2, and the air distribution unit includes a hood, an air distribution plate, and a wind chamber. The primary air G enters the air distribution unit at the bottom of the incinerator 2 through the primary air inlet 24, and then enters the air chamber for distribution. It is sent in from the bottom of the air distribution plate, and then evenly distributed to the incinerator 2 for fluidization through the wind hood on the air distribution plate. The secondary air inlet 25 is 1-3m away from the air distribution plate.

[0030] In the present invention, primary air G is introduced into the bottom of the incinerator 2 to fully fluidize the bed material I, dried fine slag and high-temperature circulating ash B in the furnace of the incinerator 2 and put them in a suspended state, while providing the oxygen required for combustion to the dense phase area to partially burn the dried fine slag. By setting a secondary air inlet 25 in the dense phase zone of the incinerator 2, and the bed material inlet 26 is located upstream of the secondary air inlet 25, and the third return material port 27, the first return material port 21, and the second return material port 23 are arranged in sequence downward along the secondary air inlet 25, on the one hand, it is ensured that the bed material I and the return material particles stably enter the dense phase zone and are fully fluidized. If the secondary air inlet 25 is lower than the aforementioned return material port, it is easy to blow away the return material particles, causing the return material particles to directly enter the dilute phase zone, shortening the residence time; on the other hand, the secondary air H is injected into the incinerator 2 at a relatively high speed, which will carry the particles in the furnace upward, and the mixing of the secondary air H and the return material particles such as the dried fine slag can be enhanced by turbulence, so as to achieve complete combustion of the return material particles such as the dried fine slag. If the secondary air inlet 25 is located lower than the aforementioned return material port, it is easy to blow the return material particles directly out of the furnace, increase the wear of the heating surface at the rear of the incinerator, and aggravate the secondary entrainment of the return material particles, thereby reducing the circulation efficiency. By arranging multiple secondary air inlets 25 in layers with a certain distance between the layers, and / or arranging multiple secondary air inlets 25 symmetrically on the same horizontal plane, the disturbance in the incinerator 2 can be further enhanced to achieve full combustion of the dried fine slag.

[0031] According to an embodiment of the present invention, the material circulation between the fluidized bed 1 and the incinerator 2 is prone to imbalance, which may cause agglomeration of the dried fine slag due to the temperature difference when returning the material, and the pressure matching between the fluidized bed 1 and the incinerator 2 is relatively difficult, which is easy to affect the stability of the operation of the drying and incineration system. In view of this, the present invention proposes to set at least one of a temperature-sensitive returner, a pressure balance valve, and a premixing section between the main material outlet 14 of the fluidized bed 1 and the first return port 21 of the incinerator 2. Among them, the temperature-sensitive returner is composed of a pneumatic returner and a temperature sensor. The temperature of the returned material is controlled at 900-1000°C by the temperature-sensitive returner to prevent the first dried fine slag D from solidifying. The pressure difference between the fluidized bed 1 and the incinerator 2 can be dynamically adjusted by the pressure balance valve, and the pressure fluctuation range can be controlled within ±50Pa to ensure that the incinerator 2 and the fluidized bed 1 operate stably and return the material smoothly. By adding a premixing section at the main material outlet of the fluidized bed 1, the dried first dried fine slag D can be fully mixed before entering the incinerator 2, thereby improving the uniformity of combustion. Similarly, at least one of a temperature-sensitive return device, a pressure balance valve, and a premixing section can be arranged between the first solid material outlet 53 and the second return port 23, and the same effect can be achieved between the incinerator 2 and the fluidized bed 1.

[0032] Continue as Figure 1As shown, the drying incineration system also includes a second gas-solid separator 3 and a returner 4. Specifically, the second gas-solid separator 3 is located downstream of the incinerator 2, and is provided with a gas-phase material inlet 31 connected to the gas-phase material outlet 22, a second exhaust port 32 for discharging flue gas K, and a second solid material outlet 33 for discharging high-temperature circulating ash B. The returner 4 is provided with a second solid material inlet 41 connected to the second solid material outlet 33, a first return material outlet 42 connected to the ash inlet 12, and a second return material outlet 43 connected to the third return material outlet 27 of the incinerator 2. In the incinerator 2, the dried fine slag is incinerated under the action of the primary air G and / or the secondary air H to produce bottom ash N and gas-phase material J, wherein the gas-phase material includes flue gas K and high-temperature circulating ash B. The gas-phase material J is discharged through the gas-phase material outlet 22 at the top of the incinerator 2, and enters the second gas-solid separator 3 through the gas-phase material inlet 31 for gas-solid separation to obtain flue gas K and high-temperature circulating ash B. The high-temperature circulating ash B is returned through the return device 4, wherein a part of the high-temperature circulating ash B leaves the return device 4 through the first return material outlet 42, and then enters the fluidized bed 1 through the ash inlet 12 to realize the return material. At the same time, the high temperature of the high-temperature circulating ash B entering the fluidized bed 1 is used to dry the high-water content gasified fine slag A, and the dried first dried fine slag D is directly introduced into the incinerator 2 for incineration, thereby reducing the endothermic gasification of a large amount of water in the incinerator 2 and improving the energy utilization efficiency; another part of the high-temperature circulating ash B is returned through the second return material outlet 43, and then enters the incinerator 2 through the third return material outlet 27 for recycling, while maintaining the required temperature of the incinerator 2.

[0033] Continue as Figure 1 As shown, the drying and incineration system also includes: a flue 7, a purification unit 8 and a chimney 9. Specifically, the flue 7 is located downstream of the second gas-solid separator 3, and is connected to the second exhaust port 32 of the second gas-solid separator 3; the purification unit 8 is connected to the outlet of the flue 7 for purifying the flue gas K; and the chimney 9 is connected to the outlet of the purification unit 8. The present invention allows the flue gas K to pass into the flue 7 to recover the waste heat of the high-temperature (900-1000°C) flue gas K generated by the incineration, which is used to heat water or other media, thereby realizing the step-by-step utilization of energy and reducing energy consumption. The flue gas K enters the purification unit 8 for purification to remove NOx, sulfur dioxide (SO2), etc. contained in the flue gas to meet the flue gas emission requirements. The purified flue gas K can be discharged through the chimney 9.

[0034] As a second aspect of the present invention, a drying and incineration method suitable for high-water-content gasified fine slag is provided, which is performed by the above-mentioned drying and incineration system suitable for high-water-content gasified fine slag, wherein the drying and incineration method comprises: drying high-water-content gasified fine slag A by using high-temperature circulating ash B in a fluidized bed 1 to obtain first dried fine slag D and water-containing material C; and incinerating the first dried fine slag D in an incinerator 2 to produce bottom ash N and gas phase material J.

[0035] In the embodiment of the present invention, the high-temperature circulating ash B is directly contacted with the high-water content gasified fine slag A, which greatly improves the drying rate of the high-water content gasified fine slag A. Compared with the traditional steam drying, the drying time is significantly shortened, and it can meet the needs of large-scale processing. In addition, by utilizing the high temperature of the high-temperature circulating ash B, the residual carbon wrapped in the ash in the high-water content gasified fine slag A can be broken under the action of heat, increasing the contact area between the residual carbon and oxygen, thereby improving the combustion efficiency of the residual carbon in the incinerator, thereby making full use of the residual carbon resources in the high-water content gasified fine slag A and reducing the waste of resources.

[0036] According to an embodiment of the present invention, the mass ratio of high-water content gasified fine slag A to high-temperature circulating ash B is 1:3-1:5, preferably 1:4. If the ratio of high-temperature circulating ash B is low (such as lower than 1:3), the heat transfer efficiency is weak, and the drying time of high-water content gasified fine slag A will be extended by 10%-15%, but the load of the drying incineration system is small, which is suitable for processing gasified fine slag with a moisture content of 50%-55%. From the perspective of balancing drying efficiency and energy consumption, the drying time is shortened to 30-40 minutes, and the activation rate of residual carbon in high-water content gasified fine slag A can be increased to 85%. Therefore, the mass ratio of high-water content gasified fine slag A to high-temperature circulating ash B can be 1:4 as the normal operating ratio. If the proportion of high-temperature circulating ash B is high (such as greater than 1:5), the heat efficiency transfer is the highest at this time, and the drying time of high-water content gasified fine slag can be shortened to 25 minutes. However, the increase in the flow rate of high-temperature circulating ash B in the drying and incineration system may cause the return device 4 to be blocked. There is a risk of blockage, and a dynamic control system is required to balance the pressure in the drying and incineration system to ensure smooth return and stable operation of the drying and incineration system.

[0037] According to an embodiment of the present invention, the drying and incineration method for high-water-content gasified fine slag provided by the present invention further includes: the water-containing material C is subjected to gas-solid separation by the first gas-solid separator 5 to obtain water-containing circulating gas E and second dried fine slag F. Further, the water-containing circulating gas E is condensed by the condenser 6 to obtain condensed water M and circulating gas L; the second dried fine slag F enters the incinerator 2 for incineration.

[0038] In the embodiment of the present invention, the water-containing material C may carry part of the second dried fine slag F with a smaller particle size and / or density, and if it is directly discharged, this part of the resources will be wasted. By setting the first gas-solid separator 5 downstream of the fluidized bed 1 to perform gas-solid separation on the water-containing material C, on the one hand, part of the second dried fine slag F carried by the water-containing material C can be recovered, and the second dried fine slag F can be returned to the incinerator 2 for incineration, so as to achieve effective utilization of resources; on the other hand, the separated high-temperature water-containing circulating gas is rich in a large amount of energy and water vapor, and the water resources contained in the water-containing circulating gas can be recovered by gas-liquid separation through the condenser 6, and at the same time, the circulating gas L can be circulated to the fluidized bed 1 to achieve the recycling of the carrier gas.

[0039] According to an embodiment of the present invention, dried fine slag (including first dried fine slag D and / or second dried fine slag F) is burned in an incinerator 2 to produce gaseous material J. The gaseous material J is separated into gas and solid by the second gas-solid separator 3 to obtain flue gas K and high-temperature circulating ash B. Further, the flue gas K absorbs heat through the flue 7 to generate steam, and the flue gas K is purified by the purification unit 8, and the purified flue gas K is directly discharged through the chimney 9. The high-temperature flue gas K (1000°C) generated by the incineration is rich in a large amount of energy. The high-temperature flue gas K is passed into the flue 7 located downstream of the second gas-solid separator 3 to absorb the heat of the high-temperature flue gas K for heating water or other media to generate steam, thereby realizing the step-by-step utilization and recycling of the heat in the flue gas K. Finally, the flue gas K enters the purification unit 8 (such as a dust collector) for purification treatment, and the purified flue gas meets the emission standards and can be directly discharged through the chimney 9. For the high-temperature circulating ash B, a part of the high-temperature circulating ash B can enter the fluidized bed 1 through the first return outlet 42 of the return device 4 to participate in the drying process of the high-water content gasified fine slag A, thereby realizing the recycling of resources and energy; another part of the high-temperature circulating ash B can be returned to the incinerator 2 for recycling or discharged from the drying and incineration system as harmless waste slag, which can be used for building materials.

[0040] According to an embodiment of the present invention, the dried fine slag is burned in the incinerator 2 to produce gaseous material J, including: introducing primary air G and secondary air H into the incinerator 2; wherein the primary air G fluidizes the bed material I and partially burns the dried fine slag; the secondary air H enhances mixing through turbulence and completely burns the dried fine slag in the incinerator 2, wherein the dried fine slag includes the first dried fine slag D and / or the second dried fine slag F, which are difficult to burn, and the temperature in the incinerator 2 needs to be increased, so the dilution of the primary air volume is reduced and the secondary air volume is increased to increase the oxygen concentration in the combustion zone, therefore, the proportion of the primary air G is 40%-60%, the proportion of the secondary air H is 60%-70%, and the total is 100%. The primary air G can be adjusted by a variable frequency fan or damper, and the bed fluidization is prioritized, so the air chamber pressure is maintained at 8-12kPa; the secondary air H dynamically adjusts the secondary air volume according to the oxygen content of the tail flue gas (target value 1.5%~3.5%).

[0041] According to an embodiment of the present invention, the oxygen content in the primary air G is 21%, which is mainly used for fluidization, and at the same time, 20%-30% of the residual carbon in the dried fine slag can be partially burned. The oxygen content in the secondary air H is 21%, which is used to supplement the oxygen in the incinerator 2 to ensure that the remaining 70%-80% of the residual carbon in the dried fine slag is completely burned, so as to fully utilize the residual carbon resources in the dried fine slag. Furthermore, the secondary air H can be introduced into the incinerator 2 in layers to avoid local hypoxia or local oxygen enrichment in the incinerator 2 to ensure the stability of combustion, wherein the timing of introducing the secondary air H is 0.5-1.0s after the dried fine slag enters the incinerator 2, so as to ensure that the oxygen concentration gradient in the dense phase area of ​​the incinerator 2 is stable and reduce the generation of NOx. Furthermore, the spacing between the layers for the introduction of the secondary air is 0.5m-1.5m.

[0042] According to an embodiment of the present invention, in addition to using high-temperature circulating ash B to dry the high-water content gasified fine slag A, the fluidized bed 1 can also use high-temperature circulating ash B to activate the residual carbon in the gasified fine slag. For the residual carbon after activation, by controlling the ratio of primary air G and secondary air H, the residual carbon in the activated dried fine slag can be fully burned. Specifically, the ratio of primary air G and secondary air H, the residual carbon crushing rate, the burnout rate of the dried fine slag in the incinerator 2, and the nitrogen oxide (NOx) emission in the flue gas are shown in Table 1. Among them, the moisture content of the high-water content gasified fine slag directly produced by industry is 60%, and the moisture content of the high-water content gasified fine slag after entering the fluidized bed for drying and activation is 0%. The gasified fine slag with a moisture content of 0% after drying and activation enters the furnace for combustion. The conditions for non-fluidized bed activation are: the high-water content gasified fine slag after traditional mechanical filtration directly enters the furnace for combustion, and there is no fluidized bed drying and activation process, wherein the water content of the high-water content gasified fine slag after traditional mechanical filtration is 35-40%.

[0043] Table 1

[0044]

[0045] Note: The feed rate of high-water content gasified fine slag is 8t / h, the mass of high-water content gasified fine slag A and high-temperature circulating ash B is 1:4, the temperature of the fluidized bed 1 is 980℃, and the temperature of the high-temperature circulating ash B is 970℃.

[0046] It can be seen from Table 1 that when the ratio of primary air G to secondary air H is the same and there is an activation of the fluidized bed 1, the residual carbon in the high-water gasified fine slag A has a higher crushing rate, and thus a larger contact area with oxygen, more complete combustion in the incinerator 2, and a lower NOx content in the flue gas K. Compared with the case without fluidized bed activation, the high-water gasified fine slag A after filter pressing is directly passed into the fluidized bed 1 (without high-temperature circulating ash B), and the energy consumption of drying the high-water gasified fine slag A will increase by 35%-40%. In addition, without the activation effect of the high-temperature circulating ash B, the residual carbon in the high-water gasified fine slag A is not crushed by thermal stress, resulting in a significant reduction in its contact area with oxygen, which leads to incomplete combustion of the dried fine slag in the incinerator 2, reduced combustion efficiency, and increased NOx content in the flue gas K. Compared with the activation of high-temperature circulating ash B, the fluidized bed 1 increases the crushing rate of residual carbon in high-water gasified fine slag A by 30%-35%, the burnout rate by 20%-25%, and the NOx emission by 40%-45%. The ratio of primary air G and secondary air H will affect the furnace temperature of incinerator 2. The greater the ratio of primary air, the lower the furnace temperature in incinerator 2, resulting in a relative decrease in the temperature of high-temperature circulating ash B, but the temperature decrease does not exceed 100°C. The temperature of high-temperature circulating ash B decreases and the activation effect will decrease when it contacts with high-water gasified fine slag A. Therefore, under the same activation of fluidized bed 1, increasing the ratio of secondary air H can fully burn the residual carbon.

[0047] According to an embodiment of the present invention, the flow rate of the secondary air H can be dynamically adjusted according to the flow rate of the dried fine slag, wherein the flow rate of the secondary air H is 1.5-2.0m 3 / kg (dried fine slag). For example, when the flow rate of dried fine slag is 10t / h, the secondary air volume is 15,000-20,000m 3 / h.

[0048] In summary, the present invention directly contacts and dries the high-temperature circulating ash B with the high-water content gasified fine slag A, realizes efficient heat transfer, significantly shortens the drying time, and improves the drying efficiency. When the high-water content gasified fine slag A contacts the high-temperature circulating ash B, the thermal stress breaks the residual carbon wrapped in the ash, increases the contact area between the residual carbon and oxygen, and is easier to combine with oxygen during the incineration process, fully burns and releases energy, improves the conversion rate of residual carbon, and reduces energy waste. By combining the fluidized bed 1 and the incinerator 2, and the ash after incineration is returned to the fluidized bed 1 as circulating ash. This circulation mode realizes the dual recycling of materials and energy, which saves resources and reduces costs. In traditional independent drying and incineration systems, materials and energy cannot be effectively circulated. In the present invention, the circulating ash not only serves as a drying heat source, but also can continuously participate in the material circulation in the drying and incineration system, reducing additional energy consumption and material input. The waste heat from the high-temperature flue gas generated by incineration is used to heat water or other media, realizing energy cascade utilization and reducing overall energy consumption. The steam generated can be used for factory power or heating, improving energy efficiency and reducing dependence on external energy. The efficient drying and incineration process, as well as the efficient energy utilization and recycling of high-temperature circulating ash, significantly reduce the processing cost and resource utilization of high-water-content gasification fine slag.

[0049] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A drying and incineration system suitable for high-water-content gasified fine slag, characterized in that: The drying and incineration system comprises: a carbon circulation system consisting of a fluidized bed and an incineration device; The fluidized bed is provided with a feed port for high-water-content gasified fine slag to enter, an ash material inlet for receiving high-temperature circulating ash, a discharge port for discharging water-containing materials, a main material outlet for discharging first dried fine slag, and a fluidized bed furnace for the high-temperature circulating ash to dry the high-water-content gasified fine slag; The incineration device comprises an incinerator for incinerating the dried fine slag entering the furnace of the incinerator, the incinerator is provided with a first return port connected to the main material outlet, and a gas phase material outlet located at the top of the incinerator for discharging gas phase material, the gas phase material comprises: flue gas and the high temperature circulating ash; Wherein, the moisture content of the high-water-content gasified fine slag is ≥60%, and the temperature of the high-temperature circulating ash is 1000-1200°C.

2. The drying and incineration system according to claim 1, characterized in that: The drying and incineration system further comprises: a flue gas circulation system consisting of a first gas-solid separator and a condenser; The first gas-solid separator is located downstream of the fluidized bed and is used to perform gas-solid separation on the water-containing material to obtain the water-containing circulating gas and the second dried fine slag, wherein the first gas-solid separator is provided with a feed port connected to the discharge port, a first exhaust port for discharging the water-containing circulating gas, and a first solid material outlet for discharging the second dried fine slag; The condenser is provided with an air inlet connected to the first exhaust port, a drain port for discharging condensed water, and a carrier gas outlet for discharging circulating gas.

3. The drying and incineration system according to claim 2, characterized in that: The fluidized bed is also provided with a carrier gas inlet connected to the carrier gas outlet; The incinerator is also provided with a second material return port connected to the first solid material outlet, a primary air inlet for primary air to enter and a slag discharge port for discharging bottom slag located at the bottom of the furnace of the incinerator, and a secondary air inlet for secondary air to enter and a bed material inlet for bed material to enter located in the dense phase zone of the incinerator; Wherein, the gaseous material and the bottom ash are formed by incinerating the dried fine slag, and the dried fine slag includes the first dried fine slag and / or the second dried fine slag; the bed material inlet is located upstream of the secondary air inlet, and the secondary air inlet is one or more, and the multiple secondary air inlets are arranged in layers, and the spacing between layers is 0.5m-1.5m.

4. The drying and incineration system according to claim 3, characterized in that: The incineration device also includes: A second gas-solid separator, located downstream of the incinerator, is provided with a gas-phase material inlet connected to the gas-phase material outlet, a second exhaust port for discharging the flue gas, and a second solid material outlet for discharging the high-temperature circulating ash; and The material return device is provided with a second solid material inlet connected to the second solid material outlet, a first material return outlet connected to the ash material inlet, and a second material return outlet connected to the third material return outlet of the incinerator.

5. The drying and incineration system according to claim 4, characterized in that: The drying and incineration system also includes: a flue, located downstream of the second gas-solid separator and connected to a second exhaust port of the second gas-solid separator; a purification unit connected to the outlet of the flue and used for purifying the flue gas; and A chimney is connected to the outlet of the purification unit.

6. The drying and incineration system according to claim 1, characterized in that: At least one of a temperature-sensitive material return device, a pressure-balancing valve and a premixing section is arranged between the main material outlet of the fluidized bed and the first material return port of the incinerator.

7. A drying and incineration method for high-water-content gasified fine slag, performed by the drying and incineration system according to any one of claims 1 to 6, characterized in that: The drying and incineration method comprises: Drying the high-water-content gasified fine slag by using high-temperature circulating ash in a fluidized bed to obtain first dried fine slag and water-containing material; The first dried fine slag is incinerated in the incinerator to generate bottom slag and gaseous materials, wherein the gaseous materials include flue gas and the high-temperature circulating ash.

8. The drying and incineration method according to claim 7, characterized in that: The drying and incineration method also includes: The water-containing material is separated into gas and solid by the first gas-solid separator to obtain water-containing circulating gas and second dried fine slag, and the second dried fine slag is returned to the incinerator for incineration; The water-containing circulating gas is condensed by a condenser to obtain condensed water and circulating gas.

9. The drying and incineration method according to claim 8, characterized in that: The gas-phase material is separated into gas and solid by a second gas-solid separator to obtain the flue gas and the high-temperature circulating ash.

10. The drying and incineration method according to claim 8, characterized in that: introducing primary air and secondary air into the incinerator; Among them, the proportion of primary air is 40%-60%, the proportion of secondary air is 60%-70%, and the total is 100%; The primary air fluidizes the bed material and partially burns the dried fine slag; the secondary air enhances mixing through turbulence and completely burns the dried fine slag in the incinerator, the dried fine slag including the first dried fine slag and / or the second dried fine slag.

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