A sludge drying and incineration collaborative treatment system and treatment method

Abstract

The application discloses a sludge drying and incineration collaborative treatment system and treatment method, and relates to the field of sludge treatment. The system comprises: an incinerator for incinerating garbage and drying sludge, a waste heat boiler for recycling waste heat of high-temperature flue gas generated by incineration, a flue gas purification system for further recycling waste heat of flue gas and purifying the flue gas after waste heat utilization, and a sludge drying unit for realizing wet sludge drying. The high-temperature flue gas outlet of the waste heat boiler is in communication with the flue gas purification system and a cyclone mixer respectively, the cyclone mixer is also in communication with a steam output port of the sludge drying unit, and is used for realizing mixing and drying of the high-temperature flue gas and steam. The cyclone mixer is in communication with a mixed air blower, the mixed air blower is communicated to the incinerator, and is used for realizing incineration of the mixed gas after drying in the incinerator. The sludge drying unit is connected with the incinerator, and is used for realizing sludge drying and conveying to the incinerator. The application has the advantages of simple operation, high flexibility, low investment cost, no waste water generation and the like.

Description

Technical Field

[0001] This invention belongs to the field of sludge treatment technology, specifically relating to a sludge drying and incineration co-processing system and method. Background Technology

[0002] Sludge drying and co-incineration technology has become a hot topic in sludge treatment due to its significant volume and weight reduction and thorough cleaning. However, current sludge co-incineration systems typically involve drying the sludge, transporting it by vehicle to various thermal power plants, and then using different methods to deliver the dried sludge into the incinerator system for incineration.

[0003] During sludge drying, various types of drying processes generate sludge drying wastewater. For example, after anaerobic digestion, the digested sludge is filtered through a plate and frame filter press to produce filtrate. In the thermal sludge drying process, the moisture in the sludge evaporates, and the evaporated waste gas is collected after being condensed by cooling water. For instance, drying 1 ton of municipal sludge with a moisture content of 80% to 40% will generate approximately 0.667 tons of sludge drying condensate wastewater.

[0004] The condensate from sludge thermal drying has a low COD but a high total nitrogen content. Therefore, its biological treatment is challenging, requiring the addition of nutrients, resulting in high treatment costs. Even after nutrient addition, a concentrate of approximately 20% or more of the total condensate mass is still produced. Consequently, the total cost of treating sludge drying condensate is high, increasing the operational costs of sludge treatment and disposal.

[0005] Table 1. Comparison of water quality indicators of concentrated liquid and sludge thermal drying condensate wastewater

[0006] project PH COD (mg / L) <![CDATA[NH3-N(mg / L)]]> Concentrate 9.26 783 346 Sludge drying condensate 9.57 973 707 Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the high cost of wastewater treatment in the sludge drying process of the prior art, and to provide a sludge drying and incineration co-treatment system and method that is compact in structure, simple to operate, highly flexible in adjustment, low in investment cost and generates no wastewater.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A sludge drying and incineration co-processing system includes: an incinerator for incinerating waste and drying sludge; a waste heat boiler for recovering and utilizing the waste heat from the high-temperature flue gas generated during incineration; a flue gas purification system for further recovering the waste heat from the flue gas and purifying the flue gas after waste heat utilization; and a sludge drying unit for drying wet sludge. The high-temperature flue gas outlet of the waste heat boiler is connected to the flue gas purification system in one path and to the inlet of a cyclone mixer in the other. The inlet of the cyclone mixer is also connected to the steam outlet of the sludge drying unit. The cyclone mixer is used to mix and dry the flue gas after waste heat utilization in the waste heat boiler with the water vapor generated during sludge drying in the sludge drying unit. The outlet of the cyclone mixer is connected to the inlet of a mixing fan, and the outlet of the mixing fan is connected to the incinerator, allowing the mixed gas output from the cyclone mixer to enter the incinerator for combustion. The sludge drying unit is connected to the incinerator to transport the dried sludge to the incinerator for combustion.

[0010] As a further improvement of the present invention, the sludge drying unit includes a wet sludge bin, a sludge dryer, and a sludge buffer bin; a conveying pump is provided between the wet sludge bin and the sludge dryer to convey the wet sludge to the sludge dryer for drying; the inlet of the cyclone mixer is connected to the steam outlet of the sludge dryer, and the sludge outlet of the sludge dryer is connected to the sludge buffer bin for sludge buffering; the sludge buffer bin is connected to an incinerator for conveying the dried sludge to the incinerator for incineration.

[0011] As a further improvement of the present invention, the flue gas outlet pressure of the waste heat boiler is -300pa to -150pa, and the outlet pressure of the sludge dryer is -500±10pa; a baffle valve is provided on the connecting pipe between the waste heat boiler and the cyclone mixer, and the baffle valve is used to adjust the pressure of the flue gas.

[0012] As a further improvement of the present invention, the connecting pipe between the waste heat boiler and the cyclone mixer is also equipped with a flow sensor, a temperature sensor and a suction fan, which are used to transport the high-temperature flue gas in the waste heat boiler to the cyclone mixer and monitor the flow rate and temperature of the flue gas entering the cyclone mixer.

[0013] As a further improvement of the present invention, a flow sensor is provided on the connecting pipe between the conveying pump and the sludge dryer to monitor the flow rate of wet sludge entering the sludge dryer.

[0014] As a further improvement of the present invention, a temperature sensor and a suction fan are provided on the connecting pipe between the sludge dryer and the cyclone mixer, for conveying steam from the sludge dryer to the cyclone mixer and monitoring the temperature of the steam entering the cyclone mixer; a temperature sensor is provided on the connecting pipe between the cyclone mixer and the mixing fan, for monitoring the temperature of the mixed gas entering the mixing fan.

[0015] As a general technical concept, the present invention also provides a method for the co-treatment of sludge drying and incineration, employing the above-mentioned sludge drying and incineration co-treatment system, the method comprising the following steps:

[0016] The wet sludge in the wet sludge bin is transported to the sludge dryer by a transfer pump and dried to a preset moisture content in the sludge dryer; the resulting dried sludge is then transported to the incinerator to be co-burned with the waste.

[0017] The wet and hot waste steam in the sludge dryer and the high-temperature flue gas in the waste heat boiler are drawn into the cyclone mixer for mixing. After mixing, the mixture is transported by the mixing fan to the high-temperature zone of the incinerator, which is above 850°C, for incineration.

[0018] As a further improvement of the present invention, the wet heat waste steam flow rate Q in the sludge dryer 汽 The following formula is used to calculate:

[0019]

[0020] Q 汽 =(G 湿 -G 干 )*1.244, kNm 3 / h (2)

[0021] The amount of wet sludge treated is G. 湿 The moisture content of the wet sludge is ω 湿 The moisture content of the dried sludge is ω 干 Dry sludge is G 干 ; 1.244 is the volume conversion coefficient when water evaporates into water vapor.

[0022] As a further improvement of the present invention, the following equation applies to the wet and hot waste steam and high-temperature flue gas before and after mixing:

[0023] Q 汽 *H 汽 +Q 烟 *H 烟 =Q 汽 *H' 汽 +Q 烟 *H' 烟 (3)

[0024] in:

[0025] Q 汽 — Waste steam flow rate, kNm 3 / h,

[0026] H 汽 --Enthalpy of waste steam, kJ / Nm 3 ,

[0027] Q 烟 —High-temperature flue gas flow rate, kNm 3 / h,

[0028] H 烟 —Enthalpy of high-temperature flue gas, kJ / Nm 3 ,

[0029] H' 烟 —Enthalpy of high-temperature flue gas at the target temperature, kJ / Nm³ 3 ,

[0030] H' 汽 —Enthalpy of waste steam at the target temperature, kJ / Nm³ 3 .

[0031] As a further improvement of the present invention, the flow rate Q' of the mixed gas output by the mixing fan... 混合 It is calculated by the following formula:

[0032]

[0033] in,

[0034] Q' 混合 — Mixed gas flow rate, km 3 / h,

[0035] P' 混合 — Mixing fan outlet pressure, kPa

[0036] P atm —Standard pressure, kPa

[0037] k -- redundancy coefficient, which can be 1.2.

[0038] Compared with the prior art, the advantages of the present invention are as follows:

[0039] 1. The sludge drying and incineration co-processing system of the present invention, by setting up a cyclone mixer to connect the high-temperature flue gas outlet of the waste heat boiler and the steam discharge port of the sludge dryer, mixes the high-temperature flue gas after waste heat utilization in the waste heat boiler with the steam generated by drying wet sludge in the sludge dryer, realizing the drying of wet hot steam, reducing the wet hot steam condensation system in the sludge thermal drying process, preventing water vapor in the wet hot steam from entering the blower and being pressurized and condensed, saving investment, reducing the cooling water system, and the energy of the wet hot steam enters the incinerator, reducing the heat loss of the boiler from the ambient air drawn in from the environment, and improving the thermal efficiency of the incinerator.

[0040] 2. The sludge drying and incineration co-treatment method of the present invention uses high-temperature flue gas from a waste heat boiler to dry the wet heat waste steam generated during sludge drying in the sludge dryer, effectively improving the dryness of the waste steam. Furthermore, the flue gas and waste steam after heat exchange are ultimately transported from the secondary or tertiary air section of the incinerator combustion chamber to a high-temperature zone above 850°C within the incinerator for incineration via a mixing fan, achieving complete decomposition of harmful substances in the waste steam. Simultaneously, the dried sludge produced in the sludge dryer is transported into the incinerator for incineration via different conveying methods, efficiently recovering the chemical energy from the sludge. Attached Figure Description

[0041] Figure 1 This is a schematic diagram illustrating the structural principle of the sludge drying and incineration co-treatment system of the present invention.

[0042] Legend: 1. Incinerator; 2. Waste heat boiler; 3. Flue gas purification system; 4. Wet sludge bin; 5. Transfer pump; 6. Sludge dryer; 7. Sludge buffer bin; 8. Cyclone mixer; 9. Mixing fan; 10. Baffle valve; 11. Flow sensor; 12. Temperature sensor; 13. Suction fan. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0044] Example 1

[0045] like Figure 1As shown, the sludge drying and incineration co-processing system of the present invention includes: an incinerator 1 for incinerating waste and drying sludge; a waste heat boiler 2 for recovering and utilizing the waste heat from the high-temperature flue gas generated during incineration; a flue gas purification system 3 for further recovering the waste heat from the flue gas and purifying the flue gas after waste heat utilization; and a sludge drying unit for realizing the drying of wet sludge. The high-temperature flue gas outlet of the waste heat boiler 2 is connected to the flue gas purification system 3 in one path and to the inlet of a cyclone mixer 8 in the other path. The inlet of the cyclone mixer 8 is also connected to the steam outlet of the sludge drying unit. The cyclone mixer 8 is used to mix and dry the flue gas after waste heat utilization in the waste heat boiler 2 with the wet waste steam generated during sludge drying in the sludge drying unit. The outlet of the cyclone mixer 8 is connected to the inlet of a mixing fan 9, and the outlet of the mixing fan 9 is connected to the incinerator 1, so that the mixed gas output from the cyclone mixer 8 enters the incinerator 1 for combustion, thoroughly decomposing the harmful components in the wet waste steam. The sludge drying unit is connected to the incinerator 1 to transport the dried sludge to the incinerator 1 for incineration. The co-processing system of this invention generates no wastewater, thus eliminating wastewater treatment costs and resulting in lower overall costs.

[0046] It is understandable that the wet waste steam evaporated after the thermal drying of sludge is generally at its saturation temperature under the current pressure. Water corresponds to different saturation temperatures under different pressures; the higher the pressure, the higher the saturation temperature. If directly drawn into the boiler, it will condense directly after being pressurized by the fan. The transport of the condensed droplets would cause damage to the fan blades due to the high-speed impact of the droplets, and the condensed droplets could not be transported into the boiler by the airflow. Therefore, this invention uses a method of directly drawing in a small amount of high-temperature flue gas after waste heat utilization and mixing it with the wet waste steam evaporated from the sludge. The high-temperature flue gas is used to heat the wet waste steam after the thermal drying of the sludge, thereby increasing the dryness of the wet waste steam and preventing the water vapor in the wet waste steam from entering the fan and condensing after being pressurized. Since the flue gas drawn is from the waste heat boiler of the incinerator, the oxygen content in the flue gas is low, the safety of mixing hot flue gas and wet waste steam is high, the mixed gas deviates from the explosion limit, and there is no possibility of gas explosion, making it extremely safe.

[0047] In this embodiment, the sludge drying unit includes a wet sludge bin 4, a sludge dryer 6, and a sludge buffer bin 7. A conveying pump 5 is provided between the wet sludge bin 4 and the sludge dryer 6 to transport the wet sludge to the sludge dryer 6 for drying. The inlet of the cyclone mixer 8 is connected to the steam outlet of the sludge dryer 6, and the sludge outlet of the sludge dryer 6 is connected to the sludge buffer bin 7 for sludge buffering. The sludge buffer bin 7 is connected to the incinerator 1 to transport the dried sludge to the incinerator 1 for incineration. Hot flue gas and the wet hot exhaust gas from the dried sludge are mixed by the cyclone mixer 8, and then transported to the secondary air inlet of the incinerator by the mixing fan 9, and then injected into the incinerator for incineration.

[0048] It is understandable that wet heat waste steam is generated during the thermal drying process of sludge. The temperature at which water evaporates in sludge is generally above 90℃, and its dryness is low. If the dryness of wet heat waste steam is not increased by heating with flue gas, the water in the sludge will condense after being pressurized by the blower, which will threaten the operation of the blower. At the same time, it is impossible to achieve true zero wastewater generation. Therefore, it is necessary to extract high-temperature flue gas from the waste heat boiler to heat the sludge evaporation waste steam.

[0049] In this embodiment, the main steam from the waste heat boiler outlet or the extracted steam after utilization, after being depressurized and reduced to approximately 0.85–0.9 MPa, is still used as a heat source to dry the sludge. The waste heat from the flue gas after utilization in the incinerator is used to heat the wet waste steam at the dryer outlet. Only a small amount of flue gas is needed to increase the dryness of the wet waste steam evaporated from the sludge, thus not affecting existing incineration facilities. This invention can be adjusted according to different sludge loads and is also adaptable to thermal drying processes with different solids contents. A thin-layer dryer is suitable for semi-drying sludge, while a combination of a thin-layer dryer and a belt dryer can be used for complete sludge drying.

[0050] The flue gas outlet pressure of waste heat boiler 2 is -300 Pa to -150 Pa, while the outlet pressure of sludge dryer 6 generally needs to be maintained at a negative pressure of around -500 Pa to extract the continuously generated wet and hot waste steam from the dryer, preventing the wet and hot waste steam from re-condensing after reaching saturation, which would affect the drying effect of the sludge. Since the outlet pressure of waste heat boiler 2 is similar to that of sludge dryer 6, a baffle valve 10 is installed on the connecting pipe between waste heat boiler 2 and cyclone mixer 8. The baffle valve 10 is used to regulate the pressure of the extracted flue gas.

[0051] In this embodiment, a flow sensor 11, a temperature sensor 12, and an extraction fan 13 are also installed on the connecting pipe between the waste heat boiler 2 and the cyclone mixer 8. These are used to transport the high-temperature flue gas from the waste heat boiler 2 to the cyclone mixer 8 and to monitor the flow rate and temperature of the flue gas entering the cyclone mixer 8. An extraction fan 13 is added between the waste heat boiler 2 and the cyclone mixer 8, and a regulating baffle valve 10 is added to the inlet of the extraction fan 13. This baffle valve 10 can specifically be an electric / pneumatic regulating valve. For different sludge treatment volumes, waste heat flue gas at different temperature ranges can be extracted to heat the wet steam from sludge drying, providing high flexibility in adjustment.

[0052] In this embodiment, a flow sensor 11 is installed on the connecting pipe between the conveying pump 5 and the sludge dryer 6 to monitor the flow rate of wet sludge entering the sludge dryer 6. The conveying pump 5 for wet sludge is generally a screw pump or a plunger pump. The flow rate of wet sludge can be calibrated according to the rotational speed of the screw pump, while the flow rate of wet sludge can be calibrated according to the frequency of piston movement of the plunger pump.

[0053] In this embodiment, a temperature sensor 12 and a suction fan 13 are installed on the connecting pipe between the sludge dryer 6 and the cyclone mixer 8. These are used to transport steam from the sludge dryer 6 to the cyclone mixer 8 and monitor the temperature of the steam entering the cyclone mixer 8. A temperature sensor 12 is also installed on the connecting pipe between the cyclone mixer 8 and the mixing fan 9 to monitor the temperature of the mixed gas entering the mixing fan 9. The hot flue gas drawn out by the suction fan 13 mixes with the wet waste steam from the dried sludge through the cyclone mixer 8. The mixture is then transported to the secondary air inlet of the incinerator via the mixing fan 9, and then injected into the incinerator for incineration. By using the incinerator flue gas to heat the dried wet steam, the condensation system for wet steam during the sludge thermal drying process is reduced, saving investment and reducing the cooling water system. The energy of this portion of the wet steam enters the incinerator, reducing heat loss from the boiler's intake of ambient air and improving the thermal efficiency of the incinerator.

[0054] Secondary air for waste incinerators is typically drawn from the boiler room environment and then delivered into the incinerator via a secondary air fan. Its function is to enhance the turbulence of flue gas within the incinerator. The ambient air temperature is generally below 50℃, but according to GB18485, the temperature in the secondary air injection zone of the waste incinerator must be above 850℃ to achieve complete decomposition of dioxins.

[0055] In accordance with this invention, a portion of high-temperature flue gas is drawn from the waste heat boiler 2 of the waste incinerator and mixed with the hot, moist steam generated during the sludge drying process. The temperature of the mixed gas is generally much higher than 100°C. This mixture is then injected into the waste incinerator along with secondary air for further treatment, without affecting the turbulence of the secondary air. Simultaneously, harmful substances in the hot, moist waste gas evaporated during sludge drying are completely decomposed.

[0056] The secondary air system draws in ambient air at 50°C, reheats it to above 120°C, and discharges it from the boiler. The energy loss (i.e., flue gas loss) is Q1. When the secondary air system draws in mixed air at above 100°C, the energy loss from the boiler's flue gas is Q2, which is significantly less than Q1. Therefore, this invention utilizes the waste heat from the thermal drying of sludge through a secondary air system, thereby improving the boiler's thermal efficiency.

[0057] The treatment system of this embodiment is suitable for synergistic coupling of sludge thermal drying processes with most types of incinerators, including waste-to-energy plant boilers, coal-fired power plant boilers, cement kilns, biomass power plant boilers, various chamber combustion furnaces, and circulating fluidized bed boilers. Therefore, it is suitable for coupling and retrofitting with existing incineration facilities. The treatment system of this embodiment can also be coupled with flue gas recirculation and denitrification technology in incinerators. The treatment system of this embodiment has a wide range of applications, low difficulty in coupling and retrofitting, does not require additional wastewater treatment systems, and offers high flexibility for retrofitting, making it worthy of widespread promotion.

[0058] Example 2

[0059] This embodiment provides a method for the co-processing of sludge drying and incineration, employing the sludge drying and incineration co-processing system described in Embodiment 1. The method includes the following steps: wet sludge is transported by truck and unloaded into a wet sludge silo 4, then conveyed to a sludge dryer 6 via a transfer pump 5. The wet sludge is dried to a preset moisture content in the sludge dryer 6, and then conveyed to an incinerator 1 for incineration. The hot, humid waste steam forcibly evaporated from the wet sludge in the sludge dryer 6 is thoroughly mixed with the high-temperature flue gas extracted from the waste heat boiler 2 in a cyclone mixer 8, and then conveyed by a mixing fan 9 to a high-temperature zone above 850°C within the incinerator 1 for incineration.

[0060] In this embodiment, the heat source for sludge drying machine 6 can be the main steam from waste heat boiler 2 or the extracted steam after utilization, which is de-cooled and cooled to saturated steam at approximately 0.85–0.9 MPa (a small amount of desuperheating water needs to be added during the initial start-up, and the condensate released in the dryer is used as makeup water for the saturated steam tank thereafter), serving as the heat source for drying. Alternatively, heat transfer oil can be used, with additional auxiliary fuel added to heat the heat transfer oil, or the high-temperature waste gas after utilization in incinerator 1 can be used to heat the heat transfer oil as the sludge drying heat source, with the heat transfer oil heated to approximately 170°C. The heat source for sludge drying machine 6 can be flexibly selected according to actual conditions.

[0061] A certain incineration project requires the co-processing of sludge, with a designed wet sludge processing capacity of G. 湿 The moisture content of the wet sludge is ω 湿 The designed moisture content of the dried sludge is ω. 干 The dry sludge is calculated as follows:

[0062]

[0063] The flow rate of wet and hot exhaust steam at the outlet of the sludge dryer is calculated as follows:

[0064] Q 汽 =(G 湿 -G 干 )*1.244, kNm 3 / h (2)

[0065] Where: 1.244 is the volume conversion coefficient when water evaporates into water vapor, i.e., 1 m 3 Water turns into water vapor, with a volume of 1244 m³ under standard conditions. 3 .

[0066] According to the law of conservation of energy, the following equation applies to the wet and hot waste steam and high-temperature flue gas before and after mixing:

[0067] Q 汽 *H 汽 +Q 烟*H 烟 =Q 汽 *H' 汽 +Q 烟 *H' 烟 (3)

[0068] in:

[0069] Q 汽 — Waste steam flow rate, kNm 3 / h,

[0070] H 汽 --Enthalpy of waste steam, kJ / Nm 3 ,

[0071] Q 烟 —High-temperature flue gas flow rate, kNm 3 / h,

[0072] H 烟 —Enthalpy of high-temperature flue gas, kJ / Nm 3 ,

[0073] H' 烟 —Enthalpy of high-temperature flue gas at the target temperature, kJ / Nm³ 3 ,

[0074] H' 汽 —Enthalpy of waste steam at the target temperature, kJ / Nm³ 3 .

[0075] It is understandable that the temperature of the mixed gas can be set according to actual production needs. To ensure that the temperature of the mixed gas is qualified, an automatic controller is set up. The target temperature of the mixed gas can be set and adjusted in real time according to production needs. The baffle valve 10 on the flue gas suction pipe of the waste heat boiler can automatically set the temperature and automatically track and adjust the flue gas flow rate to track the temperature, ensuring that the temperature of the mixed gas after the cyclone mixer is qualified.

[0076] According to formulas (1), (2), and (3), the flow rate Q' of the mixed gas can be calculated. 混合 The operating flow rate of the extracted flue gas at the current temperature and the flow rate of the mixing fan are then calculated using the Clapeyron equation:

[0077]

[0078] in,

[0079] Q' 混合 — Mixed gas flow rate, km 3 / h,

[0080] P' 混合 — Mixing fan outlet pressure, kPa

[0081] P atm —Standard pressure, kPa

[0082] k -- redundancy coefficient, which can be 1.2.

[0083] It is understandable that the outlet pressure of a mixing fan is generally selected within the range of 2 kPa to 3 kPa. As the selection pressure for the fan, the mixed gas flow rate Q' 混合 It is mainly used for the design and selection of wind turbines. Of course, it can also be used as a monitoring indicator to show whether the hybrid wind turbine is operating normally during actual operation.

[0084] Under normal circumstances, the temperature of the wet waste steam at the outlet of the sludge dryer is 90-100℃, and the pressure of the secondary and tertiary air in the incinerator does not exceed 5 kPa, corresponding to a water vapor saturation temperature of less than 102℃. Therefore, the temperature of the wet waste steam mixed with the flue gas from the waste heat boiler only needs to exceed the saturation temperature at the outlet pressure of the mixing fan. At the same time, to allow for some adjustment margin and set an appropriate redundancy coefficient, the temperature of the cyclone mixer can be set at around 110℃ as needed. It is understandable that the higher the temperature, the greater the flow rate of the mixed gas, which will increase the power consumption of the mixing fan.

[0085] To adapt to changes in sludge load, the motor of the mixing blower 9 should be configured with frequency conversion control. The maximum operating flow rate of the mixing blower 9 can be determined by substituting the design sludge treatment load into formulas (1) to (4), and the selection parameters of the mixing blower 9 can be determined after the blower parameters are determined.

[0086] Meanwhile, once the design load of the sludge, the moisture content of the wet sludge, and the moisture content of the dried sludge are determined, the required flue gas flow rate Q under the maximum design load can be determined according to formula (3) and the target control temperature after the cyclone mixer. 烟 This allows us to determine the cross-sectional area of ​​the flue gas extraction pipe.

[0087] This invention can be adjusted according to different sludge loads and is also adaptable to thermal drying processes with different solids contents. It can cover sludge semi-drying (moisture content reduced to 40%–65%) and sludge full drying (moisture content below 30%).

[0088] The sludge drying and incineration co-processing system of the present invention can be applied to new projects as well as to the renovation of various incineration facilities. It has a small footprint, low investment cost, and realizes the sharing of the processing capacity of incineration facilities and flue gas purification facilities, and has high promotion value.

[0089] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A sludge drying and incineration co-treatment system, characterized in that, include: The system comprises an incinerator (1) for incinerating waste and drying sludge, a waste heat boiler (2) for recovering and utilizing the waste heat from the high-temperature flue gas generated during incineration, a flue gas purification system (3) for further recovering the waste heat from the flue gas and purifying the flue gas after waste heat utilization, and a sludge drying unit for achieving the drying of wet sludge. The high-temperature flue gas outlet of the waste heat boiler (2) is connected in one path to the flue gas purification system (3) and in another path to the inlet of a cyclone mixer (8). The inlet of the cyclone mixer (8) is also connected to the steam outlet of the sludge drying unit. The cyclone mixer (8) is used to mix and dry the flue gas after waste heat utilization in the waste heat boiler (2) with the steam generated by sludge drying in the sludge drying unit. The output port of the cyclone mixer (8) is connected to the input port of the mixing fan (9), and the output port of the mixing fan (9) is connected to the incinerator (1) to realize the mixed gas output from the cyclone mixer (8) entering the incinerator (1) for combustion. The sludge drying unit is connected to the incinerator (1) to realize the dried sludge being transported to the incinerator (1) for combustion. The sludge drying unit includes a wet sludge bin (4), a sludge dryer (6), and a sludge buffer bin (7); a conveying pump (5) is provided between the wet sludge bin (4) and the sludge dryer (6) to realize the conveying of wet sludge to the sludge dryer (6) for drying treatment; the inlet of the cyclone mixer (8) is connected to the steam outlet of the sludge dryer (6), and the sludge outlet of the sludge dryer (6) is connected to the sludge buffer bin (7) to realize the buffering of dried sludge; the sludge buffer bin (7) is connected to the incinerator (1) to realize the conveying of dried sludge to the incinerator (1) for incineration.

2. The sludge drying and incineration co-treatment system according to claim 1, characterized in that, The flue gas outlet pressure of the waste heat boiler (2) is -300pa to -150pa, and the outlet pressure of the sludge dryer (6) is -500±10pa; a baffle valve (10) is provided on the connecting pipe between the waste heat boiler (2) and the cyclone mixer (8), and the baffle valve (10) is used to adjust the pressure of the flue gas.

3. The sludge drying and incineration co-treatment system according to claim 2, characterized in that, The connection pipe between the waste heat boiler (2) and the cyclone mixer (8) is also equipped with a flow sensor (11), a temperature sensor (12) and a suction fan (13) to realize the high temperature flue gas in the waste heat boiler (2) to be transported to the cyclone mixer (8) and to monitor the flue gas flow rate and flue gas temperature entering the cyclone mixer (8).

4. The sludge drying and incineration co-treatment system according to claim 3, characterized in that, A flow sensor (11) is installed on the connecting pipe between the conveying pump (5) and the sludge dryer (6) to monitor the flow rate of wet sludge entering the sludge dryer (6).

5. The sludge drying and incineration co-treatment system according to claim 4, characterized in that, A temperature sensor (12) and a suction fan (13) are provided on the connecting pipe between the sludge dryer (6) and the cyclone mixer (8) to transport steam from the sludge dryer (6) to the cyclone mixer (8) and to monitor the temperature of the steam entering the cyclone mixer (8); a temperature sensor (12) is provided on the connecting pipe between the cyclone mixer (8) and the mixing fan (9) to monitor the temperature of the mixed gas entering the mixing fan (9).

6. A method for the co-treatment of sludge by drying and incineration, characterized in that, The sludge drying and incineration co-treatment system according to any one of claims 1 to 5, the method includes the following steps: The wet sludge in the wet sludge bin (4) is transported to the sludge dryer (6) by the conveying pump (5) and dried to the preset moisture content in the sludge dryer (6); the dried sludge is then transported to the incinerator (1) and co-fired with the garbage. The wet heat waste steam in the sludge dryer (6) and the high temperature flue gas in the waste heat boiler (2) are drawn into the cyclone mixer (8) for mixing. After mixing, the mixture is transported to the high temperature zone above 850°C in the incinerator (1) by the mixing fan (9) for incineration.

7. The method for co-processing sludge drying and incineration according to claim 6, characterized in that, The wet heat waste steam flow rate Q in the sludge dryer (6) 汽 The following formula is used to calculate: （1） ， （2） The amount of wet sludge treated is G. 湿 The moisture content of wet sludge is The moisture content of the dried sludge is Dry sludge is G 干 ; 1.244 is the volume conversion coefficient when water evaporates into water vapor.

8. The method for co-processing sludge drying and incineration according to claim 7, characterized in that, For the wet and hot waste steam and high-temperature flue gas before and after mixing, the following equation holds: （3） in: Q 汽 — Waste steam flow rate, kNm 3 / h, H 汽 --Enthalpy of waste steam, kJ / Nm 3 , Q 烟 —High-temperature flue gas flow rate, kNm 3 / h, H 烟 —Enthalpy of high-temperature flue gas, kJ / Nm 3 , H ， 烟 —Enthalpy of high-temperature flue gas at the target temperature, kJ / Nm³ 3 , H ， 汽 —Enthalpy of waste steam at the target temperature, kJ / Nm³ 3 .

9. The method for co-processing sludge drying and incineration according to claim 7, characterized in that, The flow rate Q of the mixed gas output by the mixing fan (9) ， 混合 It is calculated by the following formula: （4） in, Q ， 混合 — Mixed gas flow rate, km 3 / h, P ， 混合 — Mixing fan outlet pressure, kPa P atm —Standard pressure, kPa k -- redundancy coefficient, set to 1.2.

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