A sludge dewatering, drying and carbonization integrated system

Abstract

The present invention discloses an integrated system for sludge dewatering, drying and carbonization, which includes a dewatering system and a carbonization system connected to the dewatering system; the dewatering system includes: a dewatering and drying unit; a water storage unit; a sludge conditioning tank unit; a sewage tank unit; a hot water tank unit; a first tail gas treatment unit; the carbonization system includes: a sludge carbonization unit; a heat exchanger unit; a conveyor unit; a second tail gas treatment unit. The present invention can maximize the utilization of the heat generated during the carbonization process, save the operation cost, and the sludge dried by the dewatering equipment enters the carbonization equipment for continuous treatment, ensuring the continuity of the process.

Description

Technical Field

[0001] The present invention belongs to the technical field of sludge treatment processes, and particularly relates to an integrated system for sludge dehydration, drying and carbonization. Background Art

[0002] At present, sludge carbonization equipment is combined with high-temperature direct or indirect sludge drying equipment. The high-temperature tail gas discharged from the carbonization equipment is introduced into the sludge drying equipment to dry the sludge. If the tail gas directly contacts the sludge in the drying equipment, it will cause a large amount of dust and volatile substances to gasify in advance, and the high dust concentration poses an explosion risk. If it is indirect contact, under high-temperature conditions, the volatile substances in the sludge will also gasify in advance. In this way, on the one hand, the tail gas discharged from the high-temperature drying equipment has a high temperature and the energy cannot be effectively utilized, resulting in great waste. On the other hand, there are many volatile gases in the tail gas, and the tail gas treatment cost is high.

[0003] When the existing integrated plate and frame filter press for dehydration and drying operates, hot water is required to indirectly heat the sludge cake in the filter press chamber. After the hot water flows through the filter press and releases heat, the temperature decreases. When this part of water is used again, a separate heat source is required to heat it up to a certain temperature before use, and this process requires additional consumption of a large amount of energy. Summary of the Invention

[0004] To solve the above technical problems, one technical solution adopted by the present invention is:

[0005] An integrated system for sludge dehydration, drying and carbonization, comprising a dehydration system, a carbonization system and a tail gas treatment system connected to the dehydration system;

[0006] The dehydration system includes:

[0007] A drying unit: used for squeezing and dehydrating sludge and heating it up;

[0008] A water storage unit: used to provide clean water source for the drying unit;

[0009] A sludge conditioning tank unit: storing sludge to be treated;

[0010] A sewage tank unit: storing sewage flowing out after passing through the drying unit;

[0011] A hot water tank unit: used to provide high-temperature hot water for the drying unit;

[0012] A vacuum pump unit (16): discharging the tail gas of the drying unit (11);

[0013] The carbonization system includes:

[0014] A sludge carbonization unit;

[0015] Heat exchanger unit: Absorbs the high-temperature flue gas generated by the sludge carbonization unit for heating water source;

[0016] Conveyor unit: Conveys the carbon produced by the sludge carbonization unit;

[0017] Induced draft fan unit (24): Discharges the low-temperature tail gas generated by the heat exchanger unit (22).

[0018] Furthermore, in the dehydration system, the water storage unit is connected to the drying unit in two paths through a squeezing pump and a flushing pump, and the sludge conditioning tank unit is connected to the drying unit through a sludge feeding pump, and the sludge feeding pump is used to convey the sludge in the sludge conditioning tank unit to the drying unit.

[0019] Furthermore, the sewage tank unit is connected to the filtrate outlet end of the drying unit, and the filtrate generated by the drying unit directly enters the sewage tank unit.

[0020] Furthermore, the drying unit (11) is connected to the tail gas treatment system (3) through a vacuum pump unit (16), and the heat exchanger unit (22) is connected to the tail gas treatment system (3) through an induced draft fan unit (24), and the tail gas treatment system (3) is used for the tail gas generated by the drying unit (11) and the heat exchanger unit (22).

[0021] Furthermore, the water outlet end of the hot water tank unit is connected to the drying unit through a hot water pump to supply the hot water in the hot water tank unit to the drying unit, and the water inlet end of the hot water tank unit is connected to the water outlet end of the heat exchanger unit for storing the high-temperature hot water generated in the heat exchanger unit, where the temperature of the high-temperature hot water is 70°C to 100°C.

[0022] Furthermore, the water inlet end of the heat exchanger unit is connected to the conveyor unit, and the air inlet end is connected to the sludge carbonization unit. The sludge carbonization unit provides high-temperature flue gas, and the heat exchanger unit uses the high-temperature flue gas to heat the return water.

[0023] Furthermore, the water inlet end of the heat exchanger unit is connected to the drying unit, and the low-temperature return water generated by the drying unit directly enters the heat exchanger unit.

[0024] Furthermore, the conveyor unit is a conveyor with a heat exchange jacket, and the conveyor unit is also connected to the drying unit. The conveyor unit heats the low-temperature return water generated by the drying unit through the heat exchange jacket in the conveyor unit to generate medium-temperature return water, and finally enters the heat exchanger unit.

[0025] Further, the drying unit (11) can be a low-temperature disk-type vacuum indirect dryer or a dehydration and drying integrated plate-and-frame filter press. The drying unit is connected to the sludge carbonization unit. The sludge generated after dehydration by the drying unit enters the sludge carbonization unit. The sludge carbonization unit is connected to a conveyor unit, and the conveyor unit is used to transport the high-temperature carbon produced by the sludge carbonization unit.

[0026] Advantages of the present invention:

[0027] When the carbonization equipment of the present invention is in operation, it will discharge the high-temperature exhaust gas after combustion. At the same time, the high-temperature carbon discharged by the carbonization equipment also needs to be cooled. The high-temperature carbon and the high-temperature exhaust gas after combustion discharged by the carbonization equipment are used to heat the hot water required for the operation of the drying section of the filter press or the low-temperature disk indirect dryer. The heated hot water is used to dry the sludge. The dried sludge enters the carbonization equipment for carbonization treatment. The high-temperature carbon and high-temperature exhaust gas discharged during the carbonization process heat the hot water used by the dehydrator. Operating in this way can maximize the utilization of the heat generated during the carbonization process, save operating costs, and the sludge dried by the dehydration equipment enters the carbonization equipment for further treatment, ensuring the continuity of the process. Description of the drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a schematic diagram of the system structure;

[0030] Description of the reference numerals:

[0031] 1. Dehydration system; 11. Drying unit; 12. Water storage unit; 121. Pressing pump; 122. Flushing pump; 13. Sludge conditioning tank unit; 131. Inlet sludge pump; 14. Sewage tank unit; 15. Hot water tank unit; 151. Hot water pump; 16. Vacuum pump unit; 2. Carbonization system; 21. Sludge carbonization unit; 22. Heat exchanger unit; 23. Conveyor unit; 24. Induced draft fan unit; 3. Tail gas treatment system. Specific embodiments

[0032] The following will elaborate on the preferred embodiments of the present invention in conjunction with the drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention. Specific embodiment 1:

[0034] A sludge dewatering, drying and carbonization integrated system, comprising a dewatering system 1 and a carbonization system 2 connected to the dewatering system 1; the drying unit in Embodiment 1 preferably uses an integrated dewatering and drying machine;

[0035] The dewatering system 1 includes:

[0036] A drying unit 11: used for squeezing and dehydrating sludge and heating it up; specifically, in the dewatering system 1, the water storage unit 12 is connected to the drying unit 11 in two paths through a squeezing pump 121 and a flushing pump 122, and the sludge conditioning tank unit 13 is connected to the drying unit 11 through a sludge feeding pump 131. The sludge feeding pump 131 is used to transport the sludge in the sludge conditioning tank unit 13 to the dewatering and drying unit 11. The drying unit 11 is an integrated dewatering and drying plate and frame filter press. The drying unit 11 is connected to the sludge carbonization unit 21. The sludge produced after dewatering and drying by the drying unit 11 enters the sludge carbonization unit 21. The sludge carbonization unit 21 is connected to a conveyor unit 23. The conveyor unit 23 is used to transport the high-temperature carbon produced by the sludge carbonization unit 21.

[0037] A water storage unit 12: used to provide clean water source for the drying unit 11;

[0038] A sludge conditioning tank unit 13: stores the sludge to be treated;

[0039] A sewage tank unit 14: stores the sewage flowing out after passing through the drying unit 11; specifically, the sewage tank unit 14 is connected to the filtrate outlet end of the drying unit 11, and the filtrate produced by the drying unit 11 directly enters the sewage tank unit 14.

[0040] A hot water tank unit 15: used to provide high-temperature hot water for the drying unit 11; specifically, the water outlet end of the hot water tank unit 15 is connected to the drying unit 11 through a hot water pump 151 to supply the hot water in the hot water tank unit 15 to the drying unit 11. The water inlet end of the hot water tank unit 15 is connected to the water outlet end of the heat exchanger unit 22, and is used to store the high-temperature hot water produced by the heat exchanger unit 22, where the temperature of the high-temperature hot water is 70°C to 100°C.

[0041] The drying section of the above integrated dewatering and drying machine can also be independently a specific low-temperature disk type vacuum indirect drying machine.

[0042] A vacuum pump unit 16: discharges the tail gas of the drying unit 11; specifically, the drying unit 11 is connected to the tail gas treatment system 3 through a vacuum pump 16;

[0043] The carbonization system 2 includes:

[0044] Sludge carbonization unit 21; in this embodiment, a layer of water-cooled outer wall is provided outside the sludge carbonization unit (21), and the water-cooled wall of the sludge carbonization unit (21) can also be an effective component of the heat exchanger unit (22).

[0045] Heat exchanger unit 22: Absorb the high-temperature flue gas generated by the sludge carbonization unit 21 to heat the water source; specifically, the water inlet end of the heat exchanger unit (22) is connected to the conveyor unit (23), and the air inlet end is connected to the sludge carbonization unit (21). The sludge carbonization unit (21) provides high-temperature flue gas, and the heat exchanger unit (22) uses the high-temperature flue gas to heat the return water.

[0046] Conveyor unit 23: Convey the carbon generated by the sludge carbonization unit 21; specifically, the conveyor unit 23 is a conveyor with a heat exchange jacket. The conveyor unit 23 is also connected to the drying unit 11. The conveyor unit 23 heats the low-temperature return water generated by the drying unit 11 through the heat exchange jacket in the conveyor unit 23 to generate medium-temperature return water, while cooling the high-temperature carbon, and finally enters the heat exchanger unit 22. The heat exchanger unit 22 is connected to the tail gas treatment system through the induced draft fan 24;

[0047] Induced draft fan unit 24: Discharge the low-temperature tail gas generated by the heat exchanger unit 22.

[0048] Tail gas treatment system 3:

[0049] During the drying process of the drying unit, ammonia and hydrogen sulfide in the sludge will emit into the tail gas. After the tail gas is washed and treated, wastewater containing ammonia and hydrogen sulfide will be generated. The sludge carbonization unit 21 will discharge tail gas containing sulfur dioxide and nitrogen oxides. After the generated tail gas is washed and treated, wastewater containing sulfate and nitrate will be generated. The two parts of wastewater are disposed of centrally. The substances in the wastewater can be neutralized, reducing the consumption of chemicals for tail gas treatment and also reducing the later wastewater treatment cost. Specific embodiment 2:

[0051] A sludge dewatering, drying and carbonization integrated system, including a dewatering system 1 and a carbonization system 2 connected to the dewatering system 1;

[0052] The dewatering system 1 includes:

[0053] Drying unit 11: used to press and dehydrate sludge and heat it up; specifically, in the dehydration system 1, the water storage unit 12 is connected to the drying unit 11 in two paths through a pressing pump 121 and a flushing pump 122. The sludge conditioning tank unit 13 is connected to the drying unit 11 through a sludge feeding pump 131, and the sludge feeding pump 131 is used to transport the sludge in the sludge conditioning tank unit 13 to the drying unit 11. The drying unit 11 is connected to the tail gas treatment system 3 through a vacuum pump unit 16. The drying unit 11 is an integrated dehydration and drying plate and frame filter press. The drying unit 11 is connected to the sludge carbonization unit 21. The sludge produced after dehydration and drying by the drying unit 11 enters the sludge carbonization unit 21. The sludge carbonization unit 21 is connected to a conveyor unit 23, and the conveyor unit 23 is used to transport the high-temperature carbon produced by the sludge carbonization unit 21. Specifically, the drying unit is an integrated dehydration and drying plate and frame filter press or a low-temperature disk indirect dryer.

[0054] Water storage unit 12: used to provide clean water source for the drying unit 11;

[0055] Sludge conditioning tank unit 13: stores the sludge to be treated;

[0056] Sewage tank unit 14: stores the sewage flowing out after passing through the drying unit 11; specifically, the sewage tank unit 14 is connected to the filtrate outlet end of the drying unit 11, and the filtrate produced by the drying unit 11 directly enters the sewage tank unit 14.

[0057] Hot water tank unit 15: used to provide high-temperature hot water for the drying unit 11; specifically, the water outlet end of the hot water tank unit 15 is connected to the drying unit 11 through a hot water pump 151 to supply the hot water in the hot water tank unit 15 to the drying unit 11. The water inlet end of the hot water tank unit 15 is connected to the water outlet end of the heat exchanger unit 22, and is used to store the high-temperature hot water generated in the heat exchanger unit 22, where the temperature of the high-temperature hot water is 70°C - 100°C.

[0058] Vacuum pump unit 16: discharges the tail gas discharged from the drying unit 11;

[0059] The carbonization system 2 includes:

[0060] Sludge carbonization unit 21;

[0061] Heat exchanger unit 22: Absorb the high-temperature flue gas generated by the sludge carbonization unit 21 to heat the water source; the water inlet end of the heat exchanger unit 22 is connected to the drying unit 11, and the low-temperature return water generated by the drying unit 11 directly enters the heat exchanger unit 22. The heat exchanger unit 22 is connected to the tail gas treatment system 3 through the induced draft fan unit 24, and the induced draft fan unit 24 is used to discharge the tail gas generated by the heat exchanger unit 22.

[0062] Conveyor unit 23: Convey the carbon generated by the sludge carbonization unit 21, and the conveyor unit 23 is also connected to the drying unit 11.

[0063] Induced draft fan unit 24: Discharge the low-temperature tail gas generated by the heat exchanger unit 22.

[0064] Tail gas treatment system 3:

[0065] During the drying process of the drying unit, ammonia and hydrogen sulfide in the sludge will volatilize into the tail gas. After the tail gas is washed and treated, wastewater containing ammonia and hydrogen sulfide will be generated. The sludge carbonization unit 21 will discharge tail gas containing sulfur dioxide and nitrogen oxides. After the generated tail gas is washed and treated, wastewater containing sulfate and nitrate will be generated. The two parts of wastewater are centrally disposed, and the substances in the wastewater can be neutralized, reducing the consumption of reagents for tail gas treatment and also reducing the later wastewater treatment cost.

[0066] In specific implementation, the tail gases of the two systems can be simultaneously introduced into the water washing tower, where a neutralization reaction occurs to generate ammonium sulfate and ammonium nitrate. In order to eliminate the odor, a deodorization tower can be connected after the reaction in the water washing tower.

[0067] Operating principle:

[0068] When the integrated plate and frame filter press for dehydration and drying operates, the sludge in the conditioning tank is pumped into the equipment by the sludge feeding pump for dehydration. When the feeding pressure reaches a certain value, the sludge feeding pump stops operating, and then the equipment enters the squeezing dehydration stage. After the squeezing dehydration is completed, the moisture content of the sludge cake is between 50% and 70%. Then it enters the negative pressure suction stage. During this stage of operation, hot water is needed to heat the sludge cake in the dehydrator. The hot water is pumped into the chamber of the dehydrator by a hot water pump, and the temperature of the hot water is between 70°C and 100°C. The hot water does not directly contact the sludge cake in the chamber, but only heats the sludge cake through indirect contact. Under the action of negative pressure suction, the boiling point of water decreases, and the water vaporized from the heated sludge cake is pumped out by a vacuum pump. The moisture content of the sludge cake decreases and can be reduced to the moisture content required for feeding the carbonization device (generally between 5% and 30%). Preferably, during actual production, a condenser can be added in front of the vacuum pump for this part of the water vapor extracted by the vacuum pump, and the water vapor is condensed by using the heat exchange water. Or a heat pump can be equipped to absorb and utilize the heat in the water vapor by using the cold-end heat exchanger of the heat pump. After the hot water pumped into the chamber by the hot water pump releases heat, its temperature decreases. If this part of the water needs to be reused, it needs to be reheated. The integrated plate and frame filter press for dehydration and drying is combined with the carbonization equipment. When the carbonization equipment operates, it will discharge high-temperature carbon. This carbon is just discharged from the equipment and has a very high temperature and needs to be cooled down. At the same time, the temperature of the combustion exhaust gas discharged by the carbonization equipment is very high, and the discharged exhaust gas also contains a lot of heat. If the exhaust gas is directly discharged, a lot of energy will be wasted. After the two equipment are combined, the low-temperature return water after the integrated plate and frame filter press for dehydration and drying is used first passes through the discharging device of the carbonization device with a heat exchange jacket conveyor. The return water first exchanges heat with the high-temperature carbon discharged by the carbonization equipment to reduce the temperature of the carbon. At the same time, the low-temperature return water becomes medium-temperature return water, and the medium-temperature return water then flows into the heat exchanger to exchange heat with the high-temperature combustion exhaust gas discharged by the carbonization equipment and becomes high-temperature hot water. The heat exchanger here can be composed of two parts combined. One part is the cooling heat exchange of the carbonizer shell, and the other part is the cooling heat exchange of the high-temperature flue gas discharged by the carbonization equipment. Both are to exchange the heat generated by burning the combustible gas after carbonization. It can also be implemented as shown in Embodiment 2, where the low-temperature return water does not pass through the conveyor with a heat exchange jacket and directly enters the heat exchanger for heating. The heat exchanger here can be composed of two parts combined. One part is the cooling heat exchange of the carbonizer shell, and the other part is the cooling heat exchange of the high-temperature flue gas discharged by the carbonization equipment. Both are to exchange the heat generated by burning the combustible gas after carbonization.The return water after heating becomes high-temperature hot water, which is supplied to the integrated plate-and-frame filter press for dehydration and drying. The sludge cake after dehydration and drying by the integrated plate-and-frame filter press enters the carbonization equipment to ensure the continuous operation of the carbonization equipment. When drying the sludge, the integrated plate-and-frame filter press for dehydration and drying conducts indirect heating in a sealed state. In this working condition, no dust is generated, avoiding the explosion risk. The tail gas extracted by the equipment is dust-free and at a low temperature. Compared with the high-temperature direct or indirect drying equipment supporting traditional carbonization equipment, the heat utilization rate is high. With such combination, not only can the continuous operation of the two types of equipment be ensured, but also the heat generated during the operation is maximally recycled, saving energy and reducing the operation cost. Moreover, this combination method is not limited to the temperature of the carbonization equipment; it can be used for low-temperature, medium-temperature, and high-temperature carbonization equipment, with a wide application range.

[0069] This patent combines the heat generated during the carbonization process and the heat required for the integrated dehydration and drying process in a loop, and combines the sludge with a water content of 5-30% required for carbonization with the water content of the sludge cake of the integrated dehydration and drying machine. It solves a series of disadvantages of the traditional drying + carbonization process, such as low energy utilization rate, high tail gas treatment cost, volatile combustible gas during the drying process, and easy dust explosion.

[0070] The drying section of the above-mentioned integrated dehydration and drying machine can be separated to become a metal low-temperature disk indirect dryer. The drying principle and process are also to indirectly heat the sludge by hot water passing through the disks and the shell layer of the dryer. The hot water temperature is 70-100°C. Then, the chamber of the dryer is evacuated, and the water in the sludge will vaporize (the vaporization temperature is about 50-70°C) in a low-pressure near-vacuum environment and then be discharged from the dryer and enter the tail gas treatment system. The high-temperature hot water after the dryer releases heat enters the carbonization system to absorb heat and increase the temperature, and then returns to the dryer, and so on. The tail gas of the dryer and the tail gas of carbonization can undergo an acid-base neutralization reaction as described above.

[0071] The above are only the embodiments of the present invention, and thus do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A sludge dehydration, drying and carbonization integrated system, characterized by: It comprises a dehydration system (1), a carbonization system (2) and an exhaust gas treatment system (3) connected to the dehydration system (1); The dehydration system (1) comprises: Drying unit (11): used for squeezing, dehydrating and heating the sludge; A water storage unit (12): used to provide a clean water source to the drying unit (11); Sludge conditioning tank unit (13): storing sludge to be treated; Sewage pool unit (14): storing sewage flowing out after passing through the drying unit (11); A hot water tank unit (15): used to provide high-temperature hot water to the drying unit (11); Vacuum pump unit (16): discharges tail gas from the drying unit (11); The carbonization system (2) comprises: Sludge carbonization unit (21); Heat exchanger unit (22): absorbing high-temperature flue gas generated by the sludge carbonization unit (21) for heating water source; Conveyor unit (23): conveying the char produced by the sludge carbonization unit (21); An induced draft fan unit (24) is configured to discharge low-temperature exhaust gas generated by the heat exchanger unit (22); In the dewatering system (1), the water storage unit (12) is connected to the drying unit (11) in two ways via a squeezing pump (121) and a flushing pump (122), and the sludge conditioning tank unit (13) is connected to the drying unit (11) via a sludge inlet pump (131), and the sludge inlet pump (131) is used to transport the sludge in the sludge conditioning tank unit (13) to the drying unit (11); The conveyor unit (23) is a conveyor with a heat exchange jacket. The conveyor unit (23) is also connected to the drying unit (11). The conveyor unit (23) heats the low-temperature return water generated by the drying unit (11) through the heat exchange jacket in the conveyor unit (23) to generate medium-temperature return water, which finally enters the heat exchanger unit (22). The water inlet end of the heat exchanger unit (22) is connected to the conveyor unit (23), and the air inlet end is connected to the sludge carbonization unit (21); the sludge carbonization unit (21) provides high-temperature flue gas, and the heat exchanger unit (22) uses the high-temperature flue gas to heat medium-temperature return water; The drying unit (11) is a low-temperature disc-type vacuum indirect drying machine or a dehydration and drying integrated plate-frame filter press; the drying unit (11) is connected to the sludge carbonization unit (21); the sludge generated after dehydration by the drying unit (11) enters the sludge carbonization unit (21); the sludge carbonization unit (21) is connected to a conveyor unit (23); the conveyor unit (23) is used to transport the high-temperature carbon generated by the sludge carbonization unit (21); The drying unit (11) is connected to the exhaust gas treatment system (3) via a vacuum pump unit (16), and the heat exchanger unit (22) is connected to the exhaust gas treatment system (3) via an induced draft fan unit (24). The exhaust gas treatment system (3) is used to treat the exhaust gas generated by the drying unit (11) and the heat exchanger unit (22).

2. The integrated sludge dehydration, drying and carbonization system according to claim 1, characterized in that: The sewage pool unit (14) is connected to the filtrate outlet end of the drying unit (11), and the filtrate generated by the drying unit (11) directly enters the sewage pool unit (14).

3. The integrated sludge dehydration, drying and carbonization system according to claim 1, characterized in that: The water outlet of the hot water tank unit (15) is connected to the drying unit (11) via a hot water pump (151) for supplying hot water in the hot water tank unit (15) to the drying unit (11); the water inlet of the hot water tank unit (15) is connected to the water outlet of the heat exchanger unit (22) for storing high-temperature hot water generated in the heat exchanger unit (22), wherein the temperature of the high-temperature hot water is 70°C to 100°C.

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