A system for using wet oxidation mud cakes as resource recovery materials after baking.

Abstract

This utility model discloses a system for using wet oxidation sludge cake as a resource material after baking, including a sludge cake receiving unit, a fine crushing unit, a deep drying unit, a pulverizing unit, a grading unit, a finished product packaging unit, a cyclone separation unit, a dust removal unit, and a heat pump unit. The wet oxidation sludge cake is first pre-dried by a second hot and humid air in the receiving unit; then it is finely crushed into particles and enters the deep drying unit, where it undergoes closed-loop heat exchange with the first hot air, reducing the moisture content to ≤10% and removing low-boiling-point VOCs at a set temperature; the dried particles are then pulverized and graded to produce sludge-based filler material; the heat pump unit recovers the latent heat of the hot and humid air and condenses VOCs, reducing energy consumption by 30-50% compared to traditional processes, with no dust or odor escaping, achieving low-cost deep drying and high-value utilization of sludge.

Description

Technical Field

[0001] This utility model relates to the field of sludge dewatering treatment and resource utilization technology, and in particular to a system for using wet oxidation sludge cake as a resource material after baking. Background Technology

[0002] With the acceleration of urbanization and the continuous expansion of municipal wastewater treatment capacity in China, coupled with the rising living standards and environmental protection requirements, sludge production continues to grow rapidly. Sludge possesses both pollutant and resource attributes; improper treatment can cause serious environmental pollution. Traditional sludge treatment methods, such as landfilling and composting, not only pose a risk of secondary pollution but also suffer from low resource utilization, large land occupation, and limited product disposal options. Drying and incineration technologies are energy-intensive, require significant investment and operational expertise, and involve odor and exhaust gas treatment issues, exhibiting a noticeable NIMBY (Not In My Backyard) effect and potentially triggering public resistance. Therefore, developing efficient and environmentally friendly sludge treatment and disposal technologies is of significant practical importance.

[0003] Wet oxidation technology, as an effective sludge treatment method, is currently becoming a hot topic in sludge treatment and is expected to become one of the mainstream technologies in the future. This technology oxidizes and decomposes organic matter in sludge under high temperature and high pressure conditions, efficiently removing bound water within and between sludge particles, significantly improving the filtration and settling properties of the sludge, thereby achieving sludge reduction, harmlessness, and stabilization. One type, "complete wet oxidation technology for sludge," uses high temperature and high pressure conditions (such as the reaction conditions disclosed in a foreign scientific literature, 250 ℃, 5.4 MPa), which can completely oxidize most of the organic matter in the sludge, dewatering it to form inorganic sand, which can ultimately be used as a building material raw material. Another type, "partial wet oxidation technology for sludge," uses medium temperature and medium pressure conditions (such as 160-220 ℃, 1.5-3.2 MPa), which not only significantly reduces equipment costs but also oxidizes most of the easily degradable organic matter in the sludge, retaining lignin, cellulose, and other organic matter for subsequent resource recovery. The dewatered sludge cake from partial wet oxidation mainly consists of cellulose, hemicellulose, and inorganic fine sand (CaCO3, SiO2), similar to the composition of pulp raw materials. After pretreatment, it can be used as filler for containers for flowers and seedlings, molded pulp products, and cardboard. However, the dewatered sludge cake contains some low-boiling-point volatile organic compounds, making it difficult to meet the requirements for use as a raw material for packaging paper. Therefore, the above-mentioned problem has become an urgent issue to be addressed in the resource utilization of dewatered sludge cake from wet oxidation treatment as a raw material for packaging paper. Overcoming these shortcomings will greatly broaden the scope of sludge resource utilization, further improve the economic benefits of sludge treatment, and strongly promote low-carbon, low-cost, and high-quality operation of the sludge industry. Utility Model Content

[0004] The present invention aims to overcome the defects in the prior art and provide a system for using wet oxidation sludge cake as a resource material after baking. By integrating high-temperature heat pump technology and multi-stage drying-pulverization process, it achieves synergistic optimization of deep sludge drying and resource utilization, and obtains sludge-based filler with no low-boiling-point volatile organic compounds and uniform particle size distribution.

[0005] To achieve the above objectives, this utility model provides a system for using wet oxidation mud cake as a resource material after baking, comprising: The mud cake receiving unit is used to receive wet oxidation mud cake and exchange heat with the second hot and humid air, so that the wet oxidation mud cake is transformed into a pre-dried mud cake and the second hot and humid air is transformed into a third hot and humid air. The fine crushing unit, which is connected to the mud cake receiving unit, is used to crush the pre-dried mud cake to obtain finely crushed mud particles. The deep drying unit has a mud inlet, a mud outlet, a first hot air inlet, and a second humid hot air outlet. The mud inlet is connected to the fine crushing unit and is used to exchange heat and mass with the first hot air after fine crushing, so that the fine crushed mud particles are transformed into devolatilized and deeply dried mud particles and the first hot air is transformed into second humid hot air. The second humid hot air outlet of the deep drying unit is connected to the air inlet of the mud cake receiving unit to provide the mud cake receiving unit with the required second humid hot air. The crushing unit, which is connected to the mud outlet of the deep drying unit, is used to crush the mud particles after devolatilization and deep drying into crushed mud particles. The grading unit, which is connected to the crushing unit, is used to screen the crushed mud particles into graded coarse mud particles and graded fine mud particles. The finished product packaging unit, which is connected to the grading unit, is used to package the graded fine mud particles into finished resource products. The cyclone separator unit has its air inlet connected to the air outlet of the mud cake receiving unit. It is used to separate mud particles in the third hot and humid air to form the fourth hot and humid air. The separated mud particles are the first recovered mud particles. The dust removal unit has its air inlet connected to the air outlet of the cyclone separator unit, and is used to further remove mud particles from the fourth humid hot air to form the fifth humid hot air, wherein the removed mud particles are the second recovered mud particles. The heat pump unit has its air inlet connected to the air outlet of the dust removal unit, and is used to convert the fifth humid hot air into the first hot air. The air outlet of the heat pump unit is connected to the first hot air inlet of the deep drying unit to provide the required first hot air to the deep drying unit.

[0006] The heat pump unit is further configured to include a heat exchanger, an evaporator, a compressor, a condenser, a fan, and an expansion valve. The compressor, condenser, expansion valve and first evaporator are connected by pipelines to form a refrigerant path; The inlet of the hot-side pipe of the heat exchanger is connected to the air outlet of the dust removal unit, the outlet of the hot-side pipe of the heat exchanger is connected to the inlet of the hot-side pipe of the first evaporator, the outlet of the hot-side pipe of the first evaporator is connected to the inlet of the second heat exchange pipe of the heat exchanger, the outlet of the cold-side heat exchange pipe of the heat exchanger is connected to the inlet of the cold-side pipe of the condenser, the outlet of the cold-side pipe of the condenser is connected to the inlet of the fan, and the outlet of the fan is connected to the air inlet of the deep drying unit.

[0007] A further configuration is provided: a second evaporator is also provided on the refrigerant pipeline between the first evaporator and the compressor, and the second evaporator is connected to an external steam unit or electric heater for supplemental heating.

[0008] The grading unit is further configured to be connected to the crushing unit for returning the graded coarse mud particles to the crushing unit for further crushing.

[0009] The cyclone separation unit is further configured to be connected to the grading unit for feeding the first recycled sludge particles into the grading unit.

[0010] The dust removal unit is further configured to be connected to the grading unit for feeding the second recycled sludge particles into the grading unit.

[0011] The setting is further defined as follows: the particle size of the finely crushed mud particles is ≤5mm.

[0012] The further configuration is as follows: the deep drying unit includes a rotary kiln, which is a short rotary kiln or a three-cylinder rotary structure.

[0013] The temperature range of the first hot air is further set to 80℃-200℃.

[0014] The particle size of the graded mud particles is further set to 1-100 μm.

[0015] Compared with existing technologies, this utility model achieves synergistic optimization of deep sludge drying and resource utilization by integrating high-temperature heat pump technology with multi-stage drying-pulverization process. The specific beneficial effects are as follows: 1. Low-energy deep drying: The system uses a high-temperature heat pump to dehumidify and heat the humid air in a closed loop. The system only needs to supplement a small amount of external steam to maintain a drying temperature of 80-200 ℃. Compared with traditional direct-fired hot air furnaces or steam drum drying, the overall energy consumption is reduced by 45%-50%, significantly reducing operating costs.

[0016] 2. Thorough removal of low-boiling-point volatile organic compounds (VOCs): The deep drying unit operates in an environment of 80-200 ℃, which can fully volatilize and remove low-boiling-point VOCs such as alcohols, aldehydes, ketones, and benzene compounds remaining in the wet oxidation sludge cake at the set temperature; the heat pump unit condenses and enriches VOCs through a two-stage evaporator, meeting the "Odor Pollutant Emission Standard" (GB 14554-93) and subsequent VOC limit requirements for paperboard raw materials.

[0017] 3. Precise and controllable particle size, improving the performance of paperboard fillers: The integrated process of fine crushing-pulverizing-grading can stabilize the final particle size of mud particles at 1-100um (preferably 5-50um), avoid the loss of ultrafine powder (<1um), reduce the roughness of paperboard, improve the filler retention rate, and at the same time improve the tensile strength, ring crush strength and surface smoothness of paperboard.

[0018] 4. The system is closed, with no secondary dust or odor: the cyclone separator + bag / cartridge dust collector combination has an efficiency of ≥99.5%; all dust-laden hot air circulates in a closed duct, with no visible dust or odor escaping from the site, and can be installed in the suburbs of cities or industrial parks, effectively mitigating the NIMBY effect.

[0019] 5. Modular layout and small footprint: The deep drying unit adopts a short rotary kiln or a three-cylinder rotary structure, and the heat pump unit can be arranged in a double-layer three-dimensional manner. The entire system occupies only 40%-50% of the area of ​​a belt dryer with the same processing capacity, making it suitable for on-site construction in sewage treatment plants or centralized sludge pretreatment centers.

[0020] 6. Multi-stage utilization of waste heat, significant carbon emission reduction: The heat pump unit recovers the latent heat of the wet air and reuses it for preheating and drying the mud cake; the system's exhaust gas temperature is ≤45 ℃, which can reduce carbon emissions throughout the year. The emissions have demonstrative significance for achieving the "carbon neutrality" goal of wastewater treatment plants.

[0021] 7. Resource productization and good economic efficiency: The treated sludge-based filler meets the requirements of "Inorganic Fillers for Recycled Papermaking" (QB / T4908-2016) and can replace 10%–45% of calcium carbonate or talc, reducing the raw material costs of papermaking enterprises. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the principle structure of a system for using wet oxidation mud cake as a resource material after baking.

[0023] The following reference numerals are marked on the accompanying drawings: U1, Mud cake receiving unit; U2, Fine crushing unit; U3, Deep drying unit; U31, Mud inlet; U32, Mud outlet; U33, First hot air inlet; U34, Second hot and humid air outlet; U4, Crushing unit; U5, Grading unit; U6, Finished product packaging unit; U7, Cyclone separator unit; U8, Dust removal unit; U9, Heat pump unit; U10, Gas purification unit; C1, Heat exchanger; C2, First evaporator; C3, Second evaporator; C4, External steam unit; C5, Compressor; C6, Condenser; C7, Fan; C8, Expansion valve; OSW (External Sludge Cake); OSP (Sludge Product); S1 (Sludge Cake After Preliminary Drying); S2 (Sludge Particles After Fine Crushing); S3 (Sludge Particles After Deviation-Deep Drying); S4 (Sludge Particles After Crushing); S5 (Sludge Coarse Particles After Grading); S61 (First Recycled Sludge Particles); S62 (Second Recycled Sludge Particles); S7 (Sludge Fine Particles After Grading). W1, condensate; G1, First hot wind; G2, Second humid hot wind; G3, Third humid hot wind; G4, Fourth humid hot wind; G5, Fifth humid hot wind; G6, Sixth cold wind; G7, Seventh cold wind. Detailed Implementation

[0024] The following describes a specific embodiment of the present invention in detail with reference to the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.

[0025] This utility model discloses a system for using wet oxidation sludge cake (OSW) as a resource material after baking. Figure 1 As shown, the system includes a cake receiving unit U1, a fine crushing unit U2, a deep drying unit U3, a pulverizing unit U4, a grading unit U5, a finished product packaging unit U6, a cyclone separation unit U7, a dust removal unit U8, a heat pump unit U9, and a gas purification unit U10. The gas purification unit U10 is used to treat the waste gas generated by the system so that it meets the emission standards before being discharged.

[0026] In this embodiment, the cake receiving unit U1 receives and stores the wet oxidation cake OSW (with a moisture content of about 40%) from various wastewater treatment plants after wet oxidation dehydration. The wet oxidation cake OSW undergoes heat and mass exchange with the second hot and humid air G2 from the deep drying unit U3 in the cake receiving unit U1 to achieve preliminary drying, thereby further reducing the moisture content of the cake. Since the water in the cake is basically free water, it evaporates quickly under the action of the second hot and humid air G2, and the moisture content of the cake is expected to drop to about 30%. At the same time, the low-boiling-point volatile organic compounds in the cake are also removed. The wet oxidation cake OSW is transformed into the preliminarily dried cake S1, and after the second hot and humid air G2 cools and humidifies, it is transformed into the third hot and humid air G3.

[0027] In this embodiment, the fine crushing unit U2 is connected to the bottom of the mud cake receiving unit U1. The fine crushing unit U2 crushes the pre-dried mud cake S1 from the mud cake receiving unit U1 into finely crushed mud particles S2 of uniform size. The average particle size of the finely crushed mud particles S2 is ≤5mm. The fine crushing unit U2 is preferably a double-stage screenless crusher, a roller crusher, an impact crusher, a jaw crusher, or other similar devices.

[0028] In this embodiment, the deep drying unit U3 has a mud inlet U31, a mud outlet U32, a first hot air inlet U33, and a second humid hot air outlet U34. Its mud inlet U31 is connected to the front-end fine crushing unit U2, and its mud outlet U32 is connected to the rear-end crushing unit U4. Its first hot air inlet U33 is connected to the air outlet of the heat pump unit U9, and its second humid hot air outlet U34 is connected to the air inlet of the mud cake receiving unit U1. Thus, the deep drying unit U3 utilizes the first hot air G1 from the heat pump unit U9 and the hot air from the fine crushing unit U2... After being finely crushed, the mud particles S2 undergo heat and mass exchange, thereby significantly reducing the moisture content of the finely crushed mud particles S2. At the same time, low-boiling-point volatile organic compounds are volatilized from the mud particles, resulting in deeply dried mud particles S3 after the low-boiling-point volatile organic compounds are baked off at a set temperature. The moisture content is generally ≤10%. The first hot air G1 absorbs the moisture in the finely crushed mud particles S2 and is cooled down and then converted into the second humid hot air G2. Specifically, the deep drying unit U3 includes a rotary kiln, which is preferably a short rotary kiln or a three-cylinder rotary structure.

[0029] In this embodiment, the inlet of the crushing unit U4 is connected to the sludge outlet U32 of the deep drying unit U3. The crushing unit U4 crushes the sludge particles S3 after devolatilization and deep drying from the deep drying unit U3 into crushed sludge particles S4. The outlet of the crushing unit U4 is connected to the inlet of the grading unit U5, and the outlet of the grading unit U5 is connected to the finished product packaging unit U6. The grading unit U5 is used to screen the crushed sludge particles S4 from the crushing unit U4 to obtain graded coarse sludge particles S5 and graded fine sludge particles S7. The average particle size of the graded fine sludge particles S7 is 1-100 μm, preferably 5-50 μm. Ultrafine particles (particle size <1 μm) can easily reduce the retention rate of sludge-based fillers, and excessively large particle sizes can increase the roughness of the paperboard, affecting its appearance and feel. The graded fine sludge particles S7 are then transported to the finished product packaging unit U6 for packaging into a resource-recovered product OSP for external sale. This resource-recovered product OSP conforms to the "Inorganic Fillers for Recycled Paper" (QB / T According to 4908-2016, it can replace 10%–45% of calcium carbonate or talc powder, reducing the raw material cost of papermaking enterprises; preferably, the grading unit U5 is also constructed with a conveying path connected to the crushing unit U4 for conveying the graded mud coarse particles S5 to the crushing unit U4 for re-crushing, which can effectively improve the utilization rate of mud particles.

[0030] In this system, the conveying path of wet oxidation cake (OSW) is as follows: wet oxidation cake (OSW) → cake receiving unit U1 (preliminary dried cake S1) → fine crushing unit U2 (finely crushed mud particles S2) → deep drying unit U3 (deeply dried mud particles S3) → crushing unit U4 (crushed mud particles S4) → grading unit U5 (graded fine mud particles S7) → finished product packaging unit U6 (resource recovery product finished product OSP).

[0031] In this system, the air inlet of the heat pump unit U9 is connected to the air outlet of the cake receiving unit U1, and the air outlet of the dust removal unit U8 is connected to the first hot air inlet U33 of the deep drying unit U3. The heat pump unit U9 processes the fifth humid hot air G5 discharged from the dust removal unit U8 and converts it into first hot air G1, which is then supplied to the deep drying unit U3. The first hot air G1 undergoes heat and mass exchange with the finely crushed mud particles S2 in the deep drying unit U3 to transform into second humid hot air G2. The second humid hot air G2 undergoes heat and mass exchange with the external mud cake OSW in the cake receiving unit U1 to transform into third humid hot air G3. Thus, the first hot air G1 in the deep drying unit U3... During the heat and mass exchange process with the finely crushed mud particles S2, some finer mud particles inevitably carry them downstream. Similarly, during the heat and mass exchange process between the second hot and humid air G2 and the wet oxidation mud cake OSW in the mud cake receiving unit U1, some finer mud particles also carry them downstream, resulting in a certain content of finer mud particles in the third hot and humid air G3. To ensure the continuous and stable operation of the hot air entering the heat pump unit U9, it is necessary to remove the mud particles from the third hot and humid air G3. Therefore, a cyclone separation unit U7 and a dust removal unit U8 are added between the mud cake receiving unit U1 and the heat pump unit U9 to remove the mud particles from the third hot and humid air G3.

[0032] In this embodiment, the air inlet of the cyclone separation unit U7 is connected to the air outlet of the mud cake receiving unit U1. The cyclone separation unit U7 is used to receive the third hot and humid air G3 discharged from the mud cake receiving unit U1 and separate it therein. In this way, the third hot and humid air G3 separates the mud particles to form the fourth hot and humid air G4, and at the same time, the separated first recovered mud particles S61 are recovered. Preferably, the bottom of the cyclone separation unit U7 is connected to the grading unit U5 to transport the first recovered mud particles S61 into the grading unit U5 for screening, which effectively improves the utilization rate of mud cake in the system.

[0033] In this embodiment, the air inlet of the dust removal unit U8 is connected to the air outlet of the cyclone separation unit U7, and its air outlet is connected to the air inlet of the hot air unit. The dust removal unit U8 is used to receive the fourth humid hot air G4 discharged from the cyclone separation unit U7 and remove the mud particles remaining in the fourth humid hot air G4 by passing it through a cloth bag or filter cartridge. After the mud particles are removed from the fourth humid hot air G4, the fifth humid hot air G5 is formed, and the removed second recovered mud particles S62 are recovered. Preferably, the bottom of the dust removal unit U8 is connected to the grading unit U5 to transport the second recovered mud particles S62 into the grading unit U5 for screening, which effectively improves the utilization rate of mud cake in the system.

[0034] Thus, the hot air circulation path in the system is: heat pump unit U9 (first hot air G1) → deep drying unit U3 (second humid hot air G2) → mud cake receiving unit U1 (third humid hot air G3) → cyclone separation unit U7 (fourth humid hot air G4) → dust removal unit U8 (fifth humid hot air G5) → heat pump unit U9. In this way, the hot air is recycled in the system, which effectively reduces the system energy consumption.

[0035] In this embodiment, the heat pump unit U9 uses refrigerant to complete the transfer and exchange of cold and heat, dehumidifying and heating the fifth humid hot air G5, while condensing the low-boiling-point volatile organic compounds in the hot air, thereby obtaining a high-temperature first hot air G1 free of low-boiling-point volatile organic compounds. The heat pump unit U9 specifically includes a heat exchanger C1, a first evaporator C2, a compressor C5, a condenser C6, a fan C7, and an expansion valve C8. The compressor C5, condenser C6, expansion valve C8, and first evaporator C2 are connected by pipelines to form a refrigerant path. The inlet of the hot-side pipeline of the heat exchanger C1 is connected to the outlet of the dust removal unit U8, and the outlet of the hot-side pipeline of the heat exchanger C1 is connected to the inlet of the hot-side pipeline of the first evaporator C2. The outlet of the hot-side pipe is connected to the inlet of the second heat exchange pipe of heat exchanger C1, the outlet of the cold-side heat exchange pipe of heat exchanger C1 is connected to the inlet of the cold-side pipe of condenser C6, the outlet of the cold-side pipe of condenser C6 is connected to the inlet of fan C7, and the outlet of fan C7 is connected to the air inlet of deep drying unit U3; preferably, a second evaporator C3 is also provided on the refrigerant pipe between the first evaporator C2 and the compressor C5, and the two ports of the hot-side pipe of the second evaporator C3 are respectively connected to the two ports of the external evaporation unit. The external steam unit C4 is used to provide supplementary heat source to the second evaporator C3. If the external steam cannot be provided by the attached parts of the plant area, the external steam unit C4 can be replaced by an electric heater to supplement the refrigerant.

[0036] The refrigerant's working process in heat pump unit U9 is mainly as follows: Liquid refrigerant is throttled and depressurized by expansion valve C8 to generate a low-pressure, low-temperature gas-liquid mixture. This low-temperature mixture absorbs heat from the fifth humid hot air G5 in the first evaporator C2, thus vaporizing into a low-pressure, low-temperature gas. Simultaneously, it exchanges heat with high-temperature steam provided by the second evaporator C3 and the external steam unit C4, allowing the low-pressure refrigerant gas to completely vaporize into a low-pressure, low-temperature superheated gas. The low-temperature, low-pressure superheated gaseous refrigerant is compressed into a high-temperature, high-pressure gas in compressor C5. This high-temperature, high-pressure gas enters condenser C6, releasing heat to the sixth cold air G6 on the cold side and condensing into a liquid state, thereby heating the sixth cold air G6 on the cold side into the first hot air G1.

[0037] The main working process on the hot air side of the heat pump unit U9 is as follows: After the fifth humid hot air G5 from the dust removal unit U8 enters the heat pump unit U9, it first passes through the heat exchanger C1 and exchanges heat with the sixth cold air G6 for cooling. Then it is sent to the evaporator for further cooling and condensation, thereby condensing the low-boiling-point volatile organic compounds contained in the fifth humid hot air G5. The condensate W1 conforms to GB / T 31962-2015. After meeting the "Water Quality Standards for Wastewater Discharged into Urban Sewers", the wastewater can be discharged for treatment. The fifth hot and humid air G5 is condensed by the evaporator to form the sixth cold air G6, which is low-temperature and free of low-boiling-point volatile organic compounds. The cooled sixth cold air G6 flows back to the heat exchanger C1 to exchange heat with the fifth hot and humid air G5 and is heated to become the seventh cold air G7. Then it enters the condenser C6 to exchange heat with the high-temperature and high-pressure refrigerant gas and is heated to form the first hot air G1. Finally, it is transported back to the deep drying unit U3 by the fan C7. This cycle can significantly reduce the heat required to dry the sludge particles.

[0038] In the above scheme, the temperature of the first hot air G1 generated by the heat pump unit U9 is preferably controlled at 80-200 ℃. This temperature can not only evaporate the water in the finely crushed mud particles S2, but also prevent the organic matter in the mud particles from being decomposed and destroyed. The compressor C5 of the heat pump unit U9 is preferably controlled by frequency conversion, so that the temperature of the first hot air G1 can be adjusted in real time according to the moisture content of the mud particles.

[0039] The above-disclosed embodiments are merely examples of the present utility model. However, the present utility model is not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present utility model.

Claims

1. A system for using wet oxidation mud cake as a resource material after baking, characterized in that, include: The mud cake receiving unit is used to receive wet oxidation mud cake and exchange heat with the second hot and humid air, so that the wet oxidation mud cake is transformed into a pre-dried mud cake and the second hot and humid air is transformed into a third hot and humid air. The fine crushing unit, which is connected to the mud cake receiving unit, is used to crush the pre-dried mud cake to obtain finely crushed mud particles. The deep drying unit has a mud inlet, a mud outlet, a first hot air inlet, and a second humid hot air outlet. The mud inlet is connected to the fine crushing unit and is used to exchange heat and mass with the first hot air after fine crushing, so that the fine crushed mud particles are transformed into devolatilized and deeply dried mud particles and the first hot air is transformed into second humid hot air. The second humid hot air outlet of the deep drying unit is connected to the air inlet of the mud cake receiving unit to provide the mud cake receiving unit with the required second humid hot air. The crushing unit, which is connected to the mud outlet of the deep drying unit, is used to crush the mud particles after devolatilization and deep drying into crushed mud particles. The grading unit, which is connected to the crushing unit, is used to screen the crushed mud particles into graded coarse mud particles and graded fine mud particles. The finished product packaging unit, which is connected to the grading unit, is used to package the graded fine mud particles into finished resource products. The cyclone separator unit has its air inlet connected to the air outlet of the mud cake receiving unit. It is used to separate mud particles in the third hot and humid air to form the fourth hot and humid air. The separated mud particles are the first recovered mud particles. The dust removal unit has its air inlet connected to the air outlet of the cyclone separator unit, and is used to further remove mud particles from the fourth humid hot air to form the fifth humid hot air, wherein the removed mud particles are the second recovered mud particles. The heat pump unit has its air inlet connected to the air outlet of the dust removal unit, and is used to convert the fifth humid hot air into the first hot air. The air outlet of the heat pump unit is connected to the first hot air inlet of the deep drying unit to provide the required first hot air to the deep drying unit.

2. The system for using wet oxidation mud cake as a resource material after baking according to claim 1, characterized in that, The heat pump unit includes a heat exchanger, an evaporator, a compressor, a condenser, a fan, and an expansion valve; The compressor, condenser, expansion valve and first evaporator are connected by pipelines to form a refrigerant path; The inlet of the hot-side pipe of the heat exchanger is connected to the air outlet of the dust removal unit, the outlet of the hot-side pipe of the heat exchanger is connected to the inlet of the hot-side pipe of the first evaporator, the outlet of the hot-side pipe of the first evaporator is connected to the inlet of the second heat exchange pipe of the heat exchanger, the outlet of the cold-side heat exchange pipe of the heat exchanger is connected to the inlet of the cold-side pipe of the condenser, the outlet of the cold-side pipe of the condenser is connected to the inlet of the fan, and the outlet of the fan is connected to the air inlet of the deep drying unit.

3. The system for using wet oxidation mud cake as a resource material after baking according to claim 2, characterized in that, A second evaporator is also provided on the refrigerant pipeline between the first evaporator and the compressor. The second evaporator is connected to an external steam unit or electric heater for supplemental heating.

4. The system for using wet oxidation mud cake as a resource material after baking according to claim 1, characterized in that, The grading unit is connected to the crushing unit to return the graded coarse mud particles to the crushing unit for further crushing.

5. The system for using wet oxidation mud cake as a resource material after baking according to claim 1, characterized in that, The cyclone separation unit is connected to the grading unit to feed the first recycled sludge particles into the grading unit.

6. The system for using wet oxidation mud cake as a resource material after baking according to claim 1, characterized in that, The dust removal unit is connected to the grading unit for feeding the second recycled sludge particles into the grading unit.

7. A system for using wet oxidation mud cake as a resource material after baking according to claim 1, characterized in that, The particle size of the finely crushed mud particles is ≤5mm.

8. A system for using wet oxidation mud cake as a resource material after baking according to claim 1, characterized in that, The deep drying unit includes a rotary kiln, which is a short rotary kiln or a three-cylinder rotary structure.

9. A system for using wet oxidation mud cake as a resource material after baking according to claim 1, characterized in that, The temperature range of the first hot air is 80℃-200℃.

10. A system for using wet oxidation mud cake as a resource material after baking according to claim 1, characterized in that, The particle size of the graded mud particles is 1-100 μm.

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