Reaction sludge cooling and waste heat deep utilization system for sludge wet oxidation

Abstract

The utility model discloses a reaction sludge cooling and waste heat deep utilization system for sludge wet oxidation. The reaction sludge cooling and waste heat deep utilization system comprises a spraying unit, a sludge cooler and a sludge conditioning unit, the spraying unit is used for treating the waste gas by spraying spraying water and carrying out reverse heat and mass transfer on the waste gas and generating low-temperature reclaimed water at the same time; the sludge cooler is used for cooling the medium-temperature sludge after the wet oxidation reaction by using low-temperature reclaimed water to generate high-temperature reclaimed water; one part of the high-temperature reclaimed water returns to the spraying unit to participate in waste gas treatment, and the other part of the high-temperature reclaimed water and / or low-temperature reclaimed water from the spraying unit are / is mixed with the raw sludge for tempering, so that the temperature and fluidity of the tempered sludge are improved, deep recycling of waste heat and regulation and optimization operation are realized, the reacted sludge is cooled, the service life of the mechanical dehydration unit is prolonged, and the energy consumption is reduced. Meanwhile, waste gas and filtrate treatment is facilitated, and extra air cooling system investment is reduced.

Description

Technical Field

[0001] This utility model relates to the field of solid waste treatment and waste heat recovery and utilization technology, and in particular to a system for cooling the reaction sludge and deeply utilizing waste heat in wet sludge oxidation. Background Technology

[0002] Wet oxidation technology introduces oxygen or oxygen-enriched air into a high-temperature, high-pressure environment, causing cell wall disruption in organic solid waste. This hydrolyzes large organic molecules into smaller organic acids and CO2, facilitating solid-liquid separation and offering advantages such as low treatment cost, environmental friendliness, and small footprint. However, wet oxidation releases a significant amount of heat. Current technology involves exchanging heat between the high-temperature sludge from the wet oxidation reaction and the unreacted, low-temperature conditioning sludge (at room temperature) in a sludge heat exchanger. The high-temperature sludge is cooled to become mesophilic sludge, while the unreacted, low-temperature conditioning sludge recovers heat, reducing operating costs. However, due to the complex composition, high viscosity, and low flow rate of the sludge, and the presence of large amounts of gas (CO2, residual O2, N2, etc.) in the post-reaction sludge, heat exchange efficiency is difficult to improve. Consequently, the temperature of the mesophilic sludge after heat recovery is typically above 50°C, and in hot summer weather, it can rise to 70°C or even higher. After the high-temperature reaction, the mesophilic sludge requires further dewatering through a mechanical dewatering unit. However, the high temperature can damage this unit, and the high temperature of the filtrate produced during dewatering is detrimental to subsequent biochemical treatment. Therefore, the mesophilic sludge after the wet oxidation reaction needs further cooling through a sludge cooler. Simultaneously, increasing the inlet temperature of the pre-reaction low-temperature conditioning sludge in the sludge heat exchanger can achieve significant energy-saving benefits. Therefore, using part or all of the cooling water from the sludge cooler, which has been heated by heat exchange with the reacting mesophilic sludge, as conditioning water can achieve deep recovery of waste heat and energy saving. Furthermore, if the temperature of the conditioning water can be adjusted, the temperature of the wet oxidation reaction in the system can be controlled, thereby optimizing and regulating the system's reaction temperature. Current wet sludge oxidation technologies lack sufficient cooling of the reaction sludge and deep utilization of waste heat, and the methods for optimizing and regulating the system's reaction temperature need to be expanded. Utility Model Content

[0003] This invention aims to overcome the deficiencies in the prior art by providing a system for cooling and deeply utilizing the waste heat of wet sludge oxidation reaction. This system deeply recovers the waste heat of the sludge after reaction and uses it to heat the conditioning sludge. This not only reduces the temperature of the sludge after reaction but also controllably increases the inlet temperature of the conditioning sludge in the heat exchanger and the wet sludge oxidation reaction temperature, thereby achieving the goal of controlling the temperature of the wet sludge oxidation treatment process system and deeply utilizing thermal energy.

[0004] To achieve the above objectives, this utility model provides a system for cooling the reaction sludge and deeply utilizing waste heat in wet sludge oxidation, including a spray unit, a sludge cooler, and a sludge conditioning unit:

[0005] The spraying unit includes a spraying tower, a waste gas inlet pipe, a waste gas outlet pipe, a spraying assembly, and a liquid storage tank. The waste gas inlet pipe is installed on the spraying tower to collect and guide the waste gas to be treated generated in the sludge wet oxidation workshop and the system into the spraying tower.

[0006] The spraying assembly is installed in a spraying tower above the exhaust gas inlet pipe, and the sprayed water exchanges heat and mass with the exhaust gas flowing from bottom to top to be converted into low-temperature medium water.

[0007] The exhaust gas outlet pipe is installed on the spray tower above the spray assembly to guide the treated exhaust gas out.

[0008] The liquid storage tank is located at the bottom of the spray tower to collect the falling low-temperature water. The low-temperature water in the liquid storage tank has two outlets: one goes into the sludge cooler; the other goes into the sludge conditioning unit.

[0009] The sludge cooler is used to exchange heat between the low-temperature water from the storage tank and the medium-temperature sludge after wet oxidation to generate cooled sludge and high-temperature water. The high-temperature water has two outlets: one returns to the spray unit as spray water for the spray assembly; the other enters the sludge conditioning unit.

[0010] The sludge conditioning unit includes a first conditioning water pump and a sludge conditioning device. The first conditioning water pump is used to pump conditioning water to the sludge conditioning device. The sludge conditioning device is used to mix the conditioning water with the raw sludge to form low-temperature conditioned sludge. The conditioning water is low-temperature water from the storage tank and / or high-temperature water from the sludge cooler.

[0011] A further configuration is provided: a spray packing layer is provided inside the spray tower between the corresponding spray components and the exhaust gas inlet pipe.

[0012] A further feature is provided: a water separator is installed between the exhaust gas outlet pipe and the spray assembly inside the spray tower.

[0013] A further configuration is provided: the spray unit is equipped with a water replenishment unit.

[0014] The following configuration is further provided: the inlet end of the first conditioning water pump is connected to a conditioning water pipeline, and a first temperature and flow sensor is provided on the downstream section of the conditioning water pipeline;

[0015] A low-temperature water pipeline is installed between the storage tank and the front section of the conditioning water pipeline, and a one-way valve is installed on the low-temperature water pipeline.

[0016] A high-temperature greywater pipeline is installed between the sludge cooler and the front section of the conditioning greywater pipeline, and a regulating valve is installed on the high-temperature greywater pipeline.

[0017] The configuration is further defined as follows: a second temperature and flow sensor, a second conditioning water pump, and a conditioning water storage tank are sequentially installed along the flow direction on the middle section of the conditioning water pipeline.

[0018] The further configuration includes: the conditioning water storage tank is equipped with a reaction gas inlet pipe for introducing the reaction gas generated during the wet oxidation reaction of sludge.

[0019] Further configuration: the sludge conditioning device is a mixing and conditioning device, or a raw sludge conveying pump.

[0020] The temperature of the cooled sludge after the reaction is further set to ≤60℃.

[0021] The temperature of the water in the high-temperature stage is 20℃-55℃, and the temperature of the water in the conditioning stage is 20℃-50℃.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] 1. The wastewater from the spray unit cools the mesophilic sludge after the wet oxidation reaction through the sludge cooler. This not only ensures that the mesophilic sludge is cooled to a suitable temperature after the reaction, facilitating subsequent dewatering and biochemical treatment of the dewatered filtrate, but also allows the heated wastewater to be mixed with the low-temperature wastewater from the storage tank. Subsequently, the wastewater is mixed and conditioned with the raw sludge in the sludge conditioning device, thereby deeply recovering and utilizing heat, effectively reducing operating costs, and facilitating temperature control of the wet sludge oxidation system. This achieves tiered deep utilization of energy and optimizes system operation.

[0024] 2. After the sludge cooler heats up, the high-temperature water exchanges heat and mass with the waste gas in the spray tower, and the excess waste heat of the system is carried away by the waste gas, which is conducive to the energy balance of the system. Therefore, there is no need to build a separate air cooling system or water cooling device, which effectively reduces investment and operating costs.

[0025] 3. The temperature of water in high-temperature environments is generally in the range of 20-55℃, which is conducive to improving the treatment efficiency of waste gas. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the principle of the wet oxidation system for sludge and waste heat utilization in the present invention.

[0027] Figure 2 This is a schematic diagram of the principle of the wet oxidation system for sludge and the deep utilization of waste heat in sludge. This is a second embodiment of the present invention.

[0028] The following reference numerals are marked on the accompanying drawings:

[0029] 1. Spraying unit; 10. Spraying tower; 11. Exhaust gas inlet pipe; 12. Exhaust gas outlet pipe; 13. Fan; 14. Liquid storage tank; 15. Spraying packing layer; 16. Spraying assembly; 17. Water separator; 18. Spraying circulation pump; 19. Water replenishment unit

[0030] 2. Sludge cooler;

[0031] 3. Sludge conditioning unit; 30. Sludge conditioning device; 31. First conditioning water pump; 32. Check valve; 33. Regulating valve; 34. First temperature and flow sensor; 35. Conditioning water storage tank; 36. Second conditioning water pump; 37. Second temperature and flow sensor;

[0032] W01, Low-temperature medium water; W02, High-temperature medium water; W03, Conditioned medium water;

[0033] S01, raw sludge; S02, low-temperature conditioning sludge; S03, medium-temperature sludge after reaction; S04, cooled sludge after reaction; S05, reaction gas; S06, reaction gas after absorption. Detailed Implementation

[0034] 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.

[0035] This utility model discloses a system for cooling and deeply utilizing waste heat from wet sludge oxidation reaction sludge. Figure 1 and Figure 2 As shown, it includes a spray unit 1, a sludge cooler 2, and a sludge conditioning unit 3. Example

[0036] The spray unit 1 includes a spray tower 10, an exhaust gas inlet pipe 11, an exhaust gas outlet pipe 12, a spray assembly 16, and a storage tank 14. The exhaust gas inlet pipe 11 is installed on the spray tower 10 to collect and guide the exhaust gas to be treated generated in the sludge wet oxidation workshop and system into the spray tower 10. The exhaust gas flows from bottom to top in the spray tower 10. Preferably, a fan 13 is installed on the exhaust gas inlet pipe 11. The fan 13 can generate negative pressure in the sludge wet oxidation workshop to draw in the exhaust gas to be treated generated in the workshop and system. Inside the spray tower 10, the spray assembly 16 is located above the exhaust gas inlet pipe. The spray assembly 16 sprays spray water (high-temperature medium-temperature water WO2) from top to bottom, which flows counter-currently with the exhaust gas from bottom to top to achieve sufficient heat and mass exchange. To improve the heat and mass exchange efficiency, a spray packing layer 15 is preferably provided inside the spray tower 10 between the spray assembly 16 and the exhaust gas inlet pipe 11. In this way, the spray water can easily form a thin film in the spray packing layer 15, thereby significantly increasing the contact area between the spray water and the exhaust gas. This design achieves good heat and mass exchange, allowing the exhaust gas to cool the spray water (high-temperature medium-temperature water WO2) and convert it into low-temperature medium-temperature water WO1. Simultaneously, the spray water absorbs and deodorizes some harmful substances in the exhaust gas, achieving a dual effect of cooling the spray water (high-temperature medium-temperature water WO2) and deodorizing the exhaust gas. The exhaust gas outlet pipe 12 is located on the spray tower 10 above the spray assembly 16, preferably at the top of the spray tower 10, and is used to guide the treated exhaust gas... The exhaust gas enters the next process (soil filter or biological filter, etc.). Preferably, a water remover 17 is installed inside the spray tower 10 between the exhaust gas outlet pipe 12 and the spray assembly 16. The water remover 17 can remove the liquid droplets entrained in the flowing exhaust gas. The liquid storage tank 14 is located at the bottom inside the spray tower 10. It is used to receive and store the falling low-temperature water W01. The low-temperature water W01 in the liquid storage tank 14 has two outlets: one goes into the sludge cooler 2; the other goes into the sludge conditioning unit 3.

[0037] The sludge cooler 2 exchanges heat between the low-temperature wastewater WO1 from the storage tank 14 and the medium-temperature sludge SO3 after the wet oxidation reaction. After the reaction, the medium-temperature sludge SO3 is cooled down and transformed into cooled sludge SO4, which then enters the next process. The temperature of the cooled sludge SO4 is preferably controlled at ≤60℃. The low-temperature wastewater WO1 is heated up and transformed into high-temperature wastewater WO2. The temperature of the high-temperature wastewater WO2 is preferably controlled at 20℃-55℃. The high-temperature wastewater WO2 has two outlets: one outlet returns to the spray unit 1 as spray water for the spray assembly 16, and the high-temperature wastewater WO2 then undergoes heat and mass exchange with the waste gas to transform back into low-temperature wastewater WO1. This forms a cycle of wastewater between the spray unit 1 and the sludge cooler 2, and the circulation of wastewater is achieved by the spray circulation pump 18. The other outlet enters the sludge conditioning unit 3, so that the sludge conditioning unit 3 can fully and deeply utilize the heat of the high-temperature wastewater WO2.

[0038] The sludge conditioning unit 3 includes a first conditioning water pump 31 and a sludge conditioning device 30. The first conditioning water pump 31 is used to pump conditioning water WO3 to the sludge conditioning device 30. The sludge conditioning device 30 is used to mix the conditioning water WO3 with the raw sludge SO1 (generally with a moisture content of 75%-85%) to form low-temperature conditioning sludge SO2. The conditioning water WO3 is either low-temperature water WO1 from the storage tank 14, or high-temperature water WO2 from the sludge cooler 2, or a mixture of low-temperature water WO1 from the storage tank 14 and high-temperature water WO2 from the sludge cooler 2. The conditioning sludge formed by the sludge conditioning unit 3 then enters the wet oxidation heat exchange reaction system.

[0039] In this embodiment, the inlet end of the first conditioning water pump 31 is connected to a conditioning water pipeline. The conditioning water pipeline is divided into a front section, a middle section and a rear section along the flow direction of the conditioning water WO3. A first temperature and flow sensor 34 for real-time detection of water temperature and flow rate is installed on the rear section of the conditioning water pipeline. A low-temperature water WO1 pipeline is installed between the liquid storage tank 14 of the spray unit 1 and the front section of the conditioning water pipeline. A one-way valve 32 is installed on the low-temperature water WO1 pipeline to restrict the flow of low-temperature water WO1 from the liquid storage tank 14 to the conditioning water pipeline. A high-temperature greywater WO2 pipeline is installed between the sludge cooler 2 and the upstream section of the conditioning greywater pipeline. A regulating valve 33 is installed on the high-temperature greywater WO2 pipeline. In this way, the sludge conditioning unit 3 can regulate the temperature of the conditioning greywater WO3, preferably between 20℃ and 55℃, by means of feedback from the first temperature and flow sensor 34 and by regulating the opening of the first conditioning water pump 31, the regulating valve 33 and the one-way valve 32. Moreover, while deeply recovering waste heat, it can also regulate the reaction temperature and flowability of the wet oxidation of sludge in the system, thereby achieving the purpose of optimizing and regulating the operation of the system.

[0040] In this embodiment, there is one exhaust gas inlet pipe 11, which is located in the middle of the spray tower 10, that is, the outlet of the exhaust gas inlet pipe 11 is located above the liquid surface of the intermediate medium in the storage tank 14. In other specific embodiments, there may be two or more exhaust gas inlet pipes 11, which are located in the middle and / or lower part of the spray tower 10. The exhaust gas inlet pipe 11 is located in the lower part of the spray tower 10, that is, the outlet of the exhaust gas inlet pipe 11 is located below the liquid surface of the intermediate medium in the storage tank 14. In this way, the exhaust gas can also enter the spray tower 10 under a certain pressure.

[0041] In this embodiment, the spray unit 1 is also provided with a water replenishment unit 19.

[0042] In this embodiment, the sludge conditioning device 30 can be a mixing and conditioning device for mixing raw sludge SO1 and conditioning water WO3; the sludge conditioning device 30 can also be a raw sludge SO1 conveying pump, in which the raw sludge SO1 and conditioning water WO3 complete the dual functions of mixing and conditioning and conveying. Example

[0043] Compared with the scheme of Embodiment 1, the sludge conditioning unit 3 of Embodiment 2 further includes a second temperature and flow sensor 37, a second conditioning water pump 36, and a conditioning water storage tank 35 arranged sequentially along the flow direction of the conditioning water WO3 in the middle section of the conditioning water pipeline. The second conditioning water pump 36 is used to pump the conditioning water WO3 (low temperature water WO1 and / or high temperature water WO2) to the conditioning water storage tank 35 and store it in the conditioning water storage tank 35. This makes the system operation more stable and reliable. On the other hand, the reaction gas SO5 generated during the wet oxidation reaction of sludge can be connected to the reaction gas inlet pipe at the bottom of the conditioning water storage tank 35. The waste heat of the reaction gas SO5 can be recovered more deeply, and the CO2 in the reaction gas SO5 can be absorbed to improve the scale inhibition characteristics of the system. The reaction gas SO6 absorbed by the water is discharged into the spray unit 1 through the blower 13 to complete the purification treatment.

[0044] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A system for cooling reaction sludge and deeply utilizing waste heat in wet sludge oxidation, characterized in that, Includes a spray unit, a sludge cooler, and a sludge conditioning unit: The spraying unit includes a spraying tower, a waste gas inlet pipe, a waste gas outlet pipe, a spraying assembly, and a liquid storage tank. The waste gas inlet pipe is installed on the spraying tower to collect and guide the waste gas to be treated generated in the sludge wet oxidation workshop and the system into the spraying tower. The spraying assembly is installed in a spraying tower above the exhaust gas inlet pipe, and the sprayed water exchanges heat and mass with the exhaust gas flowing from bottom to top to be converted into low-temperature medium water. The exhaust gas outlet pipe is installed on the spray tower above the spray assembly to guide the treated exhaust gas out. The liquid storage tank is located at the bottom of the spray tower to collect the falling low-temperature water. The low-temperature water in the liquid storage tank has two outlets: one goes into the sludge cooler; the other goes into the sludge conditioning unit. The sludge cooler is used to exchange heat between the low-temperature water from the storage tank and the medium-temperature sludge after wet oxidation to generate cooled sludge and high-temperature water. The high-temperature water has two outlets: one returns to the spray unit as spray water for the spray assembly; the other enters the sludge conditioning unit. The sludge conditioning unit includes a first conditioning water pump and a sludge conditioning device. The first conditioning water pump is used to pump conditioning water to the sludge conditioning device. The sludge conditioning device is used to mix the conditioning water with the raw sludge to form low-temperature conditioned sludge. The conditioning water is low-temperature water from the storage tank and / or high-temperature water from the sludge cooler.

2. The sludge cooling and waste heat deep utilization system for wet sludge oxidation according to claim 1, characterized in that, Inside the spray tower, a layer of spray packing is provided between the corresponding spray components and the exhaust gas inlet pipe.

3. The sludge cooling and waste heat deep utilization system for wet sludge oxidation according to claim 1, characterized in that, A water separator is installed inside the spray tower between the exhaust gas outlet pipe and the spray assembly.

4. The sludge cooling and waste heat deep utilization system for wet sludge oxidation according to claim 1, characterized in that, The spray unit is equipped with a water replenishment unit.

5. The sludge cooling and waste heat deep utilization system for wet sludge oxidation according to claim 1, characterized in that, The inlet end of the first conditioning water pump is connected to a conditioning water pipeline, and a first temperature and flow sensor is installed on the downstream section of the conditioning water pipeline. A low-temperature water pipeline is installed between the storage tank and the front section of the conditioning water pipeline, and a one-way valve is installed on the low-temperature water pipeline. A high-temperature greywater pipeline is installed between the sludge cooler and the front section of the conditioning greywater pipeline, and a regulating valve is installed on the high-temperature greywater pipeline.

6. The sludge cooling and waste heat deep utilization system for wet sludge oxidation according to claim 5, characterized in that, The second temperature and flow sensor, the second conditioning water pump, and the conditioning water storage tank are sequentially installed along the flow direction in the middle section of the conditioning water pipeline.

7. The sludge cooling and waste heat deep utilization system for wet sludge oxidation according to claim 6, characterized in that, The conditioning water storage tank is equipped with a reaction gas inlet pipe for introducing the reaction gas generated during the wet oxidation reaction of sludge.

8. The sludge cooling and waste heat deep utilization system for wet sludge oxidation according to claim 1, characterized in that, The sludge conditioning device is either a mixing and conditioning device or a raw sludge conveying pump.

9. The sludge cooling and waste heat deep utilization system for wet sludge oxidation according to claim 1, characterized in that, The temperature of the cooled sludge after the reaction is ≤60℃.

10. A system for cooling reaction sludge and deeply utilizing waste heat in wet sludge oxidation according to claim 1, characterized in that, The temperature of the water in the high-temperature process is 20℃-55℃, and the temperature of the water in the conditioning process is 20℃-50℃.

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