Efficient sludge treatment process

Abstract

The invention relates to an efficient sludge treatment process, which mainly comprises a defibering and size mixing pretreatment device, a low-temperature damp and hot coalification system, a sewage pretreatment and detection feedback system, a wet oxidation system, a wet oxidation steam regeneration system, a wet oxidation pressure-stabilizing exhaust system, a sewage treatment system and a waste gas treatment system. All devices and systems of the process are coordinated for treatment, organic energy of the sludge and the organic wet garbage slurry is fully utilized and converted into heat to be used by the process, and a product is a coal compound, has a high heat value and is used as fuel. And the efficient treatment effects of reduction, harmlessness and recycling are achieved.

Description

Technical Field

[0001] The invention relates to a sludge high-efficiency treatment process, which is mainly used in the treatment of wet garbage containing organic matter such as municipal sludge in the environmental protection industry. Background Art

[0002] Municipal sludge is an inevitable product of municipal sewage treatment plants and sewage treatment. It is a solid-liquid mixture produced in various units of the sewage treatment system. It is a byproduct of the sewage treatment process. It has a high water content, is easy to rot, has a strong odor, and contains a large number of pathogens, parasite eggs, and heavy metals such as cadmium, chromium, lead, and mercury, as well as toxic, harmful, and carcinogenic substances that are difficult to degrade. Therefore, when sludge that has not been properly treated enters the environment, it directly causes secondary pollution to water bodies, soil, and the atmosphere, posing a serious threat to my country's ecological environment and people's activities.

[0003] At present, the commonly used sludge treatment technologies in my country mainly include sludge concentration technology, sludge dehydration technology, sludge anaerobic digestion technology, high-temperature aerobic fermentation technology, sludge thermal drying technology, etc. The treated sludge needs to be safely disposed. At present, the commonly used disposal methods in my country are land use (agricultural use), incineration, and sanitary landfill, but these disposal methods have now encountered obstacles to varying degrees: land use has high requirements for sludge quality, and heavy metals and other toxic and harmful substances in sludge often exceed the standard; due to the high water content of sludge, the energy consumption of incineration is too high, which is not ecological and environmentally friendly; sanitary landfill usually encounters the embarrassing situation of having no land to bury.

[0004] How to improve sludge treatment efficiency, reduce energy consumption, and recycle it is a difficult problem in the current sludge treatment process. Summary of the invention

[0005] The present invention aims to provide a sludge efficient treatment process.

[0006] The technical solution used by the present invention to solve the technical problem is: A highly efficient sludge treatment process, mainly including a delamination and slurry pretreatment device, a low-temperature wet-heat coalification system, a sewage pretreatment and detection feedback system, a wet oxidation system, a wet oxidation steam regeneration system, a wet oxidation pressure-stabilizing exhaust system, a sewage treatment system, and a waste gas treatment system. The sludge and organic wet garbage slurry are mixed and slurried for pretreatment, and various process devices and systems are coordinated to fully utilize the organic energy of the sludge and organic wet garbage slurry to convert it into heat for the process itself. The product is coalification with a high calorific value and is used as fuel. The effect of efficient treatment of reduction, harmlessness, and resource utilization is achieved.

[0007] (1) The processing steps of the present invention are: (a) Dispersion and slurry pretreatment: Mix the sludge and waste organic wet garbage slurry in proportion, disperse and disperse, adjust into slurry material, and remove sand. The ratio of sludge to waste organic wet garbage slurry is 1:0.1~1, and the sewage pretreatment and detection feedback system detects data and automatically adjusts; (b) Low-temperature wet-heat coalification: The slurry material of step (a) is transported into the low-temperature wet-heat coalification system, directly heat-exchanged with the coalification liquid for preheating, and then enters the heater, directly mixed with the high-temperature steam generated by the wet oxidation regeneration steam system of step (e) and heated to 200-230°C, and wet-heat coalification reaction is performed for 0.5-1h to become coalification liquid, which is heat-exchanged with the slurry material and cooled, and then solid-liquid separation is performed. The obtained coalification product (containing 30% to 35% water) is defueled and utilized, and the coalification wastewater enters the next step; (c) Sewage pretreatment and detection feedback: The coalification sewage produced in step (b) is regulated, precipitated, and deoiled, and the pH, COD, and CL- indicators are detected and adjusted to meet the requirements. The control system feedbacks and adjusts the ratio of sludge to waste organic wet garbage slurry in step (a); (d) Wet oxidation: Add a catalyst to the pretreated wastewater in step (c), the catalyst is a copper-based catalyst, and is pumped into the system by a high-pressure pump. After heat exchange with the wastewater after the oxidation reaction, it is preheated to 230-250°C, heated (heating is required for startup, but not for normal operation, as the heat of the oxidation reaction can provide the material with the reaction temperature), mixed with compressed air online, and then enter the wet oxidizer for wet oxidation exothermic reaction. The reaction temperature is 260-280°C, the reaction pressure is 6-8MPa, and the reaction time is 3-5h. The COD degradation rate of the wastewater after the reaction is greater than 90%. The oxidized wastewater after the reaction is cooled by heat exchange, cooled, and treated to meet the discharge standards; (e) Wet oxidation steam regeneration: take part of the oxidized wastewater in step (d) into the steam generator to generate high-temperature steam of 210-230°C, which is mixed with the heated slurry material in step (b) to increase the temperature, and the non-condensable gas is automatically discharged to the waste gas treatment system; (f) Wet oxidation pressure-stabilized exhaust system: The exhaust gas and excess compressed air continuously generated by the wet oxidizer in step (d) are discharged stably and continuously by means of a pressure-stabilizing device to regulate the pressure of the wet oxidation, and are then treated in an exhaust gas treatment system to meet emission standards.

[0008] (2) The wet oxidation reactor is configured as a vertical device. The water inlet and compressed air inlet are arranged at the bottom of the reactor, and the water outlet is arranged on the upper side wall of the reactor. The liquid level is controlled by a liquid level gauge to be higher than the water outlet. A gas-liquid separator is arranged on the water outlet pipe. The gas phase port of the separator is connected to the exhaust system pipeline. The diameter is less than 1 / 5 of the exhaust main pipe and less than 40 mm. The water outlet is provided with a pressure and flow adjustment device to control the liquid level in the reactor and stabilize the pressure.

[0009] (3) The water inlet of the wet oxidation steam regeneration system is set on the upper side wall of the wet oxidation reactor, and its height is 200-300mm lower than that of the water outlet. A front pressure regulating device is set between the regenerator and the wet oxidation reactor to control the pressure stability of the wet oxidation reactor. A rear pressure regulating device is set on the regenerator outlet steam pipeline to control the pressure stability of the regenerator. A flow regulating device is set at the rear end of the pressure stabilizing device, and the steam flow is controlled and regulated by the heater temperature sensor of the low-temperature wet heat coalification system.

[0010] (4) A gas phase space with a volume of 25% to 30% is set at the top of the wet oxidation reactor. The gas outlet is connected to the wet oxidation pressure-stabilized exhaust system. The wet oxidation pressure-stabilized exhaust system is equipped with a two-stage pressure-regulated exhaust control device. The exhaust pipeline is set above the water outlet pipeline separator. The first-stage exhaust pressure control device is set between the reactor exhaust port and the gas phase pipe of the water outlet separator and is controlled by the pressure of the reactor. The second-stage exhaust pressure control device is installed at the rear end of the gas phase pipe of the water outlet separator and is controlled by the pressure at the rear end of the exhaust pressure stabilizing device. The overall effect is to continuously and stably discharge non-condensable gas and excess compressed air, ensure the reactor pressure stabilization, and ensure the safety of the rear end.

[0011] (5) The above technical solution adopted by the present invention has the following significant effects: (a) Mixing sewage sludge with waste organic wet slurry increases the organic matter content of the sludge, provides energy for subsequent treatment, and synergistically treats waste organic wet slurry, such as kitchen waste; (b) The wastewater after coalification in the present invention is more suitable for wet oxidation. While treating the wastewater, the organic energy thereof is converted into heat for the process itself, and wet heat coalification is performed, thereby saving operating costs; (c) The total processing time of the present invention is about 3.5-6 hours, which can achieve efficient and rapid processing, reduce material storage and reaction facilities, and save a lot of land and investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the process flow of the present invention.

[0013] Figure 2 It is a schematic diagram of the layout of the wet oxidation reactor of the present invention.

[0014] Figure 3 It is the material balance diagram of the whole process of the case of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples of implementation. It should be noted that many details listed in the specification are only for the purpose of enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0016] like Figure 3 As shown, taking 100t / d municipal sludge treatment, the organic wet garbage slurry is kitchen waste as an example, a sludge efficient treatment process according to the present invention includes the following steps: (a) Dispersion and slurry pretreatment: 100t / d of municipal sludge was mixed with 10t / d of kitchen waste, dispersed and dispersed, slurried, and 1.6t / d of sand was removed; (b) Low-temperature wet-heat coalification: 108.4 t / d of the slurry material from step (a) is transported into the low-temperature wet-heat coalification system, directly heat-exchanged with the coalification liquid for preheating, and then enters the heater, where it is directly mixed with 8.3 t / d of steam generated by the wet oxidation regeneration steam system in step (e) and heated to 210°C for wet-heat coalification reaction for 1 hour to become 116.7 t / d of coalification liquid, which is heat-exchanged with the slurry material and cooled before solid-liquid separation is performed. The obtained 18.47 t / d of coalification product (containing 30% water) is defueled and utilized, and 98.23 t / d of coalification wastewater enters the next step; (c) Wastewater pretreatment and test feedback: The 98.23t / d wastewater produced in step (b) was conditioned, precipitated, and degreased, and pH, COD, and CL were tested and adjusted. - The indicators meet the requirements; (d) Wet oxidation: Add 0.24t / d of copper-based catalyst to the pretreated wastewater from step (c); pump it into the system through a high-pressure pump, heat it with the wastewater after the oxidation reaction, and preheat it to 240°C, and then heat it with 8920Nm 3 / d compressed air is mixed online and enters the wet oxidizer for wet oxidation reaction. The reaction temperature is 270℃, the reaction pressure is 6MPa, and the reaction time is 3h. After the reaction, the COD of the sewage is degraded by 92%, and the total heat generated by the oxidation reaction is about 32600.7MJ. After the reaction, the oxidized sewage of 85.82t / d is cooled by heat exchange, cooled, and treated to meet the discharge standards. (e) Wet oxidation steam regeneration: take part of the oxidized wastewater in step (d) into the steam generator to generate 8.3t / d of high-temperature steam at 210°C, which is mixed with the heated slurry material in step (b) to increase the temperature, and the non-condensable gas is automatically discharged to the waste gas treatment system; (f) Wet oxidation pressure stabilization exhaust system: The exhaust gas continuously generated by the wet oxidizer in step (d) and the excess compressed air 18246Nm 3 / d The pressure of wet oxidation is regulated by the pressure stabilizing device and discharged stably and continuously, and the exhaust gas is treated by the exhaust gas treatment system to meet the emission standards.

[0017] Some material indicators of this embodiment are shown in Table 1 below:

[0018] The heat energy comparison between the heat consumption section and the heat generation section of this embodiment is shown in Table 2:

[0019] From Table 1 and Table 2 of this case, it can be seen that the efficient sludge treatment process of the present invention produces coalification with more calorific value after low-temperature wet-heat coalification reaction, which is equivalent to the calorific value of lignite and can be used as fuel; the coalified wastewater obtained after low-temperature wet-heat coalification is more suitable for wet oxidation reaction. Under the action of the catalyst, the energy of its own organic components is used to carry out rapid wet oxidation reaction, releasing a large amount of heat for the reaction materials and reactions, and there is enough excess heat for low-temperature wet-heat coalification reaction, without consuming other energy sources to generate heat. The treatment process makes full use of the organic energy of sludge and organic wet garbage slurry to provide heat for the heating and reaction of the process itself, greatly reducing the operating energy consumption. Even after increasing the proportion of organic wet garbage slurry, there is more surplus heat that can be converted into electricity and other energy for the electrical equipment of the treatment process, further reducing the operating energy consumption of the entire process.

[0020] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A highly efficient sludge treatment process, characterized in that It includes a delamination and slurry pretreatment device, a low-temperature wet heat coalification system, a sewage pretreatment and detection feedback system, a wet oxidation system, a wet oxidation steam regeneration system, a wet oxidation pressure-stabilizing exhaust system, a sewage treatment system, a waste gas treatment system, and a slurry pretreatment for mixing sludge and organic wet garbage slurry; the treatment process includes the following steps: (a) Dispersion and slurry pretreatment: Mix the sludge and waste organic wet garbage slurry in proportion, disperse and disperse them, adjust them into slurry material, and remove sand; (b) Low-temperature wet-heat coalification: The slurry material of step (a) is transported into the low-temperature wet-heat coalification system, directly heat-exchanged with the coalification liquid for preheating, and then enters the heater, and is directly mixed with the high-temperature steam generated by the wet oxidation regeneration steam system of step (e) and heated to 200-230°C for wet-heat coalification reaction for 0.5-1h to become coalification liquid, which is heat-exchanged with the slurry material and cooled, and then solid-liquid separation is performed. The obtained coalification product (containing 30% to 35% water) is defueled and utilized, and the coalification wastewater enters the next step; (c) Sewage pretreatment and detection feedback: The coalification sewage produced in step (b) is regulated, precipitated, and deoiled, and the pH, COD, and CL- indicators are detected and adjusted to meet the requirements. The control system feedbacks and adjusts the ratio of sludge to waste organic wet garbage slurry in step (a); (d) Wet oxidation: Add a catalyst to the pretreated wastewater in step (c), the catalyst is a copper-based catalyst, and is pumped into the system by a high-pressure pump. After heat exchange with the wastewater after the oxidation reaction, it is preheated to 230-250°C, heated (heating is required for startup, but not for normal operation, as the heat of the oxidation reaction can provide the material with the reaction temperature), mixed with compressed air online, and then enters the wet oxidizer for wet oxidation exothermic reaction. After the reaction is completed, the oxidized wastewater is cooled by heat exchange, cooled, de-sewaged, and treated to meet the discharge standards; (e) Wet oxidation steam regeneration: take part of the oxidized wastewater in step (d) into the steam generator to generate high-temperature steam of 210-230°C, which is mixed with the heated slurry material in step (b) to increase the temperature, and the non-condensable gas is automatically discharged to the waste gas treatment system; (f) Wet oxidation pressure-stabilized exhaust system: The exhaust gas and excess compressed air continuously generated by the wet oxidizer in step (d) are discharged stably and continuously by means of a pressure-stabilizing device to regulate the pressure of the wet oxidation, and are then treated in an exhaust gas treatment system to meet emission standards.

2. A sludge efficient treatment process according to claim 1, characterized in that The ratio of sludge from the slurry pretreatment device to waste organic wet garbage slurry is 1:0.1~1.

3. A sludge efficient treatment process according to claim 1, characterized in that The wet oxidation reaction temperature is 260-280°C, the reaction pressure is 6-8MPa, and the reaction time is 3-5h.

4. A sludge efficient treatment process according to claim 1, characterized in that The wet oxidation reactor is a vertical device. The water inlet and compressed air inlet are arranged at the bottom of the reactor, and the water outlet is arranged on the upper side wall of the reactor. The liquid level is controlled by a liquid level gauge to be higher than the water outlet. A gas-liquid separator is arranged on the water outlet pipe. The gas phase port of the separator is connected with the exhaust system pipeline, and the diameter is less than 1 / 5 of the exhaust main pipe and less than 40mm.

5. A sludge efficient treatment process according to claim 1, characterized in that The water inlet of the wet oxidation steam regeneration system is arranged on the upper side wall of the wet oxidation reactor, with a height of 200-300mm higher than the water outlet. A front pressure regulating device is arranged between the regenerator and the wet oxidation reactor to control the pressure stability of the wet oxidation reactor. A rear pressure regulating device is arranged on the steam pipeline at the outlet of the regenerator to control the pressure stability of the regenerator. A flow regulating device is arranged at the rear end of the pressure stabilizing device, and the steam flow rate is controlled and regulated by the heater temperature sensor of the low-temperature wet heat coalification system.

6. A sludge efficient treatment process according to claim 1, characterized in that A gas phase space with a volume of 25% to 30% is set on the top of the wet oxidation reactor. The gas outlet is connected to the wet oxidation pressure-stabilized exhaust system. The wet oxidation pressure-stabilized exhaust system is provided with a two-stage pressure-regulating exhaust control device. The exhaust pipeline is arranged above the water outlet pipeline separator. The first-stage exhaust pressure control device is arranged between the reactor exhaust port and the gas phase pipe of the water outlet separator and is controlled by the pressure of the reactor. The second-stage exhaust pressure control device is installed at the rear end of the gas phase pipe of the water outlet separator and is controlled by the pressure at the rear end of the exhaust pressure stabilizing device.

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