Incinerator slag wastewater collection and reuse system and method

Abstract

A kind of incineration slag wastewater collection and reuse system and method, by collecting slag wastewater and reusing to slag extractor, by incineration slag from 1000 ℃ cooling to 50 ℃ generates heat exchange, so that slag high salt recovery liquid is constantly evaporated, the salt in it can be converted into as incineration ash to be handled, water vapor generated in the cooling process passes through the second combustion chamber flue gas outlet upwards into flue gas treatment system, and the flue gas pollution generated when high-salinity wastewater is treated is solved simultaneously.The present application can reduce about 15 tons of high-salinity wastewater disposal amount and production water supplement amount per day by combining with existing system, thereby saving high-salinity wastewater treatment cost.

Description

Technical Field

[0001] This invention relates to the field of hazardous waste incineration technology, specifically to a system and method for collecting and reusing incineration slag wastewater. Background Technology

[0002] In the prior art, when treating hazardous waste, the slag produced after the rotary kiln incineration falls into the slag discharge machine. After being rapidly cooled by a water seal, the ash is conveyed by a scraper to a vibrator via a conveyor belt. The conveyor belt is inclined from bottom to top to facilitate the simultaneous drainage of excess water from the slag. The discharged slag falls onto a collection ton bag.

[0003] The slag coming off the slag discharger normally has a moisture content of around 35%. During the stacking process, a large amount of slag water is generated. According to the "National Hazardous Waste List", this slag water should be managed as hazardous waste. The wastewater needs to be collected and sprayed back into the rotary kiln. However, this disposal method is costly and is prone to melting in the rotary kiln.

[0004] The commonly used treatment method is to mix slag water with leachate and then introduce it into the leachate treatment system. However, this method has a problem: slag water is characterized by high salt content and lacks biodegradability. Mixing it into the leachate treatment system not only affects the biochemical treatment effect of the leachate treatment system, but also increases the treatment cost of slag water.

[0005] Therefore, there is a need for a method to collect and utilize slag water, which can convert high-salt slag water into incinerable ash in the existing process, so as to save water resources and reduce treatment costs. Summary of the Invention

[0006] To address the shortcomings of the aforementioned technologies, this invention provides a system and method for collecting and reusing wastewater from incinerator slag. The technical solution of this invention is: a method for collecting and reusing wastewater from incinerator slag, wherein the method comprises: receiving slag from a rotary kiln using a slag discharge device, which is a water-sealed scraper slag discharger; the slag is cooled by a water seal, and the water inside the water-sealed scraper slag discharger is evaporated;

[0007] The high-moisture slag cooled by the water-sealed scraper slag discharger is transported to the slag wastewater collection device, which is a filter press to dewater the high-moisture slag and then collect it in ton bags.

[0008] The recovered liquid from the filter press dewatering, the leachate collected in the ton bags, and the plant's circulating water are collected in a circulating water tank. The liquid in the circulating water tank is then reused in the slag discharge machine. Heat exchange occurs as the incinerator slag cools from 1000°C to 50°C, causing the recovered liquid in the slag discharge machine to continuously evaporate. The salt in the liquid can be converted into incinerator ash and treated together with the slag. The water vapor generated during the cooling process rises and enters the flue gas treatment system through the flue gas outlet of the secondary combustion chamber.

[0009] A further feature of the present invention is that the method further includes setting up several cooling pools inside the water-sealed scraper slag discharge machine according to the cooling temperature range, with the pool closest to the rotary kiln being the primary cooling pool and the pool closest to the slag discharge machine outlet being the final cooling pool. Water from the circulating water pool is introduced sequentially from the final cooling pool to the primary cooling pool according to the temperature changes of each pool, and the high-salt recovery liquid is evaporated in the primary cooling pool with the highest temperature.

[0010] The technical solution of the present invention: a system for collecting and reusing incinerator slag wastewater, including a slag discharge device, a slag wastewater collection device, and a wastewater supply device. The slag discharge device includes a water-sealed scraper slag discharger installed at the tail of a rotary kiln. The water-sealed scraper slag discharger includes a casing, a chain, a chain drive motor, and several sprockets. The casing is provided with a cooling channel. The cooling channel includes a starting end connected to the rotary kiln via a sealed hopper and an ending end on the other side. The top of the cooling channel is provided with a steam pipe connected to the secondary combustion chamber. The vertical bottom surface of the cooling channel has a wave-like undulating structure, including several crests and troughs. The troughs form pools for accumulating cooling water. The crests are spaced apart from each pool. The several troughs are divided into a primary cooling pool, a secondary cooling pool, ... a final cooling pool from the starting end to the ending end. Each cooling pool is provided with an inlet pipe, an outlet pipe, and a temperature sensor.

[0011] The chain and sprockets are laid along the undulating surface of the cooling channel. The chain is equipped with scrapers. The chain drive motor is located at both ends of the cooling channel and works in conjunction with the chain and sprockets to drive the scrapers to carry the slag through each cooling pool.

[0012] The slag wastewater collection device includes a filter press connected to a water-sealed scraper slag discharge machine, which dewaters the slag.

[0013] The wastewater supply device includes a circulating water tank, a PLC controller, several water pumps, and corresponding primary cooling tanks, secondary cooling tanks, ..., and final cooling tanks, with primary storage tanks, secondary storage tanks, ..., and final storage tanks. The circulating water tank receives circulating water from the plant area and slag recovery water obtained from the filter press. The circulating water tank is connected to the final storage tank by an inlet pipe. The inlet pipe of each cooling tank is connected to the corresponding storage tank, and the outlet pipe of each tank is connected to the storage tank of the next higher cooling tank.

[0014] Each inlet and outlet pipeline is equipped with a water pump. Each water pump and each temperature sensor are connected to the PLC controller. The PLC controller controls the start and stop of each water pump according to the temperature of each pool, and drives the circulating water to finally converge in the primary cooling pool and evaporate completely. The generated steam rises and enters the secondary combustion chamber through the steam pipeline, and finally enters the flue gas treatment system.

[0015] Using the above technical solution, the water-sealed scraper slag remover is a continuous and efficient mechanical slag removal device, mainly used to separate solid materials of a certain particle size from liquid-solid mixtures. In the incineration process, hazardous waste produces ash after being burned in a rotary kiln. The ash falls into the water-sealed scraper slag remover at the kiln tail and is scraped out into the slag box.

[0016] Existing water-sealed scraper slag discharge machines are generally installed at the bottom of the secondary combustion chamber and connected to it. There is only one water seal space inside, and the cooling water is only provided in one place, resulting in poor cooling effect. It relies on the external circulation of cooling water and needs to continuously compensate for the cooling water to achieve a rapid cooling effect.

[0017] This application proposes a multi-stage cooling pool system within the water-sealed scraper slag discharge machine, divided into cooling zones. This includes a primary cooling pool that initially contacts the high-temperature slag, a final cooling pool that cools the slag to the process temperature before discharge, and several intermediate cooling pools arranged according to process requirements. This design ensures that the slag in the final cooling pool comes into contact with newly introduced low-temperature cooling water from the circulating water tank, guaranteeing the final cooling temperature. Furthermore, it allows for progressive water replenishment between pools based on temperature sensor data. For example, if the water level in the secondary cooling pool is too high, water from that pool is introduced into the primary pool, while lower-temperature cooling water from the next lower cooling pool is added to maintain the cooling circulation temperature.

[0018] The cooling water mixed with high-salt recovery solution eventually flows into the primary cooling pool, where it comes into contact with the high-temperature slag that has just come out of the rotary kiln until it evaporates completely. The salt in the water can be converted into incineration ash and treated together with the slag.

[0019] The filter press installed at the same time dewaters the slag with high water content. The dewatered liquid is guided to the circulating water tank and then supplied to each cooling tank by the wastewater supply device. In this cycle, the collection and reuse of slag wastewater is realized.

[0020] The beneficial effects of this invention are as follows: By collecting and reusing the slag wastewater in the slag discharge machine, heat exchange occurs as the incinerator slag is cooled from 1000°C to 50°C, causing continuous evaporation of the high-salt slag recovery liquid. The salt content can be converted into incineration ash for further treatment. The water vapor generated during the cooling process rises and enters the flue gas treatment system through the secondary combustion chamber flue gas outlet, effectively solving the flue gas pollution generated during high-salt wastewater treatment. By combining this application with existing systems, approximately 15 tons of high-salt wastewater treatment volume and production water makeup volume can be reduced daily, thereby saving on high-salt wastewater treatment costs. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of an embodiment of the present invention;

[0022] Figure 2 The structure of this embodiment of the invention Figure 1 ;

[0023] Figure 3 The structure of this embodiment of the invention Figure 2 ;

[0024] Figure 4 This is a partial cross-sectional view of the slag discharge machine according to an embodiment of the present invention.

[0025] Among them, 1-rotary kiln, 2-water seal scraper slag remover, 21-chain, 22-sprocket, 23-cooling channel, 231-starting point, 232-ending point, 24-steam pipeline, 251-crest section, 252-trough section, 253-primary cooling pool, 254-final cooling pool, 261-liquid inlet pipeline, 262-liquid outlet pipeline, 263-water pump, 264-final water storage tank, 265-primary water storage tank, 3-secondary combustion chamber, 4-circulating water pool.

[0026] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual size of the product. Furthermore, the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. Detailed Implementation

[0027] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0028] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used only for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0029] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0030] like Figure 1-4 As shown, a method for collecting and reusing incinerator slag wastewater is described. The method is as follows: the slag from the rotary kiln 1 is received by a slag discharge device, which is a water-sealed scraper slag discharge machine 2. The slag is cooled by a water seal, and the water in the water-sealed scraper slag discharge machine 2 is evaporated.

[0031] The high-moisture slag cooled by the water-sealed scraper slag discharger 2 is transported to the slag wastewater collection device, which is a filter press, to dewater the high-moisture slag and then collect it in a ton bag.

[0032] The recovered liquid from the filter press dewatering, the leachate collected in the ton bag, and the plant's circulating water are collected in the circulating water tank 4. The liquid in the circulating water tank 4 is then reused in the slag discharge machine. Heat exchange occurs as the incinerator slag cools from 1000°C to 50°C, causing the recovered liquid in the slag discharge machine to continuously evaporate. The salt in the liquid can be converted into incinerator ash and treated together with the slag. The water vapor generated during the cooling process rises and enters the flue gas treatment system through the flue gas outlet of the secondary combustion chamber 3.

[0033] The method further includes setting up several cooling pools in the water-sealed scraper slag discharge machine 2 according to the cooling temperature range. The pool closest to the rotary kiln 1 is the primary cooling pool 253, and the pool closest to the slag discharge machine outlet is the final cooling pool 254. Water from the circulating water pool 4 is introduced from the final cooling pool 254 to the primary cooling pool 253 according to the temperature change of each pool, and the high-salt recovery liquid is evaporated in the primary cooling pool 253 with the highest temperature.

[0034] A wastewater collection and reuse system for incinerator slag includes a slag discharge device, a slag wastewater collection device, and a wastewater supply device. The slag discharge device includes a water-sealed scraper slag discharger 2 installed at the tail of a rotary kiln 1. The water-sealed scraper slag discharger 2 includes a casing, a chain 21, a chain 21 drive motor, and several sprockets 22. The casing is provided with a cooling channel 23. The cooling channel 23 includes a starting end 231 connected to the rotary kiln 1 via a sealed hopper, and an ending end 232 on the other side. The top of the cooling channel 23 is provided with a connection to the two... The steam pipe 24 connected to the combustion chamber 3 has a vertical bottom surface with a wave-like undulating structure, including several wave crests 251 and wave troughs 252. The wave troughs 252 form pools for accumulating cooling water. The wave crests 251 are spaced apart from each pool. The several wave troughs 252 are divided into a first-level cooling pool 253, a second-level cooling pool, ... a final cooling pool 254 in the direction from the starting end 231 to the ending end 232. Each cooling pool is equipped with an inlet pipe 261, an outlet pipe 262, and a temperature sensor.

[0035] The chain 21 and sprocket 22 are laid along the undulating surface of the cooling channel 23. The chain 21 is equipped with scrapers. The chain 21 drive motor is located at both ends of the cooling channel 23 and works in conjunction with the chain 21 and sprocket 22 to drive the scrapers to carry slag through each cooling pool.

[0036] The slag wastewater collection device includes a filter press connected to the water-sealed scraper slag discharge machine 2, which dewaters the slag.

[0037] The wastewater supply device includes a circulating water tank 4, a PLC controller, several water pumps 263, and corresponding primary water storage tanks 265, secondary water storage tanks, ..., final water storage tanks 264 for primary cooling tanks 253, secondary cooling tanks, ..., final cooling tanks 254. The circulating water tank 4 receives circulating water from the plant area and slag recovery water obtained from the filter press. The circulating water tank 4 is connected to the final water storage tank 264 by an inlet pipe 261. The inlet pipe 261 of each cooling tank is connected to the corresponding water storage tank of that tank, and the outlet pipe 262 of that tank is connected to the water storage tank of the previous cooling tank 253.

[0038] Each inlet pipe 261 and outlet pipe 262 is equipped with a water pump 263. Each water pump 263 and each temperature sensor are connected to the PLC controller. The PLC controller controls the start and stop of each water pump 263 according to the temperature of each pool, and drives the circulating water to finally converge in the primary cooling pool 253 and evaporate completely. The generated steam rises and enters the secondary combustion chamber 3 through the steam pipe 24, and finally enters the flue gas treatment system.

[0039] The water-sealed scraper slag remover 2 is a continuous and efficient mechanical slag removal device, mainly used to separate solid materials of a certain particle size from a liquid-solid mixture. In the incineration process, hazardous waste is incinerated in the rotary kiln 1, producing ash. The ash falls into the water-sealed scraper slag remover 2 at the kiln tail of the rotary kiln 1, and is then scraped out by the water-sealed scraper slag remover 2 and placed into a slag box.

[0040] The existing water-sealed scraper slag discharge machine 2 is generally installed at the bottom of the secondary combustion chamber 3 and connected to the secondary combustion chamber 3. It has only one water seal space inside and only one cooling water is provided, resulting in poor cooling effect. It relies on the external circulation of cooling water and needs to continuously compensate for the cooling water to achieve the effect of rapid cooling.

[0041] This application incorporates multiple cooling pools within the water-sealed scraper slag discharger 2, arranged in cooling zones. These include a primary cooling pool 253 that initially contacts the high-temperature slag, and a final cooling pool 254 that cools the slag to the process temperature before discharge. Several intermediate cooling pools are then installed according to process requirements. This design ensures that the slag in the final cooling pool 254 comes into contact with newly introduced low-temperature cooling water from the circulating water pool 4, guaranteeing the final cooling temperature. Furthermore, it allows for progressive water replenishment between pools based on temperature sensor data. For example, if the water level in a secondary cooling pool is too high, water from that pool is introduced into the primary pool, while lower-temperature cooling water from the next lower cooling pool is added to maintain the cooling circulation temperature.

[0042] The cooling water mixed with high-salt recovery liquid eventually flows into the primary cooling pool 253, where it comes into contact with the high-temperature slag that has just exited the rotary kiln 1 until it evaporates completely. The salt in the water can be converted into incineration ash and treated together with the slag.

[0043] The filter press installed at the same time dewaters the slag with high water content. The dewatered liquid is guided to the circulating water tank 4 and supplied to each cooling tank by the wastewater supply device. In this cycle, the collection and reuse of slag wastewater is realized.

[0044] The beneficial effects of this invention are as follows: By collecting and reusing the slag wastewater in the slag discharge machine, heat exchange occurs as the incinerator slag is cooled from 1000°C to 50°C, causing continuous evaporation of the high-salt slag recovery liquid. The salt content can be converted into incineration ash for further treatment. The water vapor generated during the cooling process rises and enters the flue gas treatment system through the flue gas outlet of the secondary combustion chamber 3, effectively solving the flue gas pollution generated during high-salt wastewater treatment. By combining this application with existing systems, approximately 15 tons of high-salt wastewater treatment volume and production water replenishment can be reduced daily, thereby saving on high-salt wastewater treatment costs.

[0045] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the protection scope of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this application.

Claims

1. A system for collecting and reusing wastewater from incinerator slag, characterized in that: The system includes a slag discharge device, a slag wastewater collection device, and a wastewater supply device. The slag discharge device includes a water-sealed scraper slag discharger installed at the tail of the rotary kiln. The water-sealed scraper slag discharger includes a casing, a chain, a chain drive motor, and several sprockets. The casing is equipped with a cooling channel, which includes a starting end connected to the rotary kiln via a sealed hopper and an ending end on the other side. The top of the cooling channel is equipped with a steam pipe connected to the secondary combustion chamber. The vertical bottom surface of the cooling channel has a wavy structure, including several crests and troughs. The troughs form pools for accumulating cooling water. The crests are spaced apart from each pool. The several troughs are divided into a primary cooling pool, a secondary cooling pool, and so on, from the starting end to the ending end, to the final cooling pool. Each cooling pool is equipped with an inlet pipe, an outlet pipe, and a temperature sensor. The chain and sprockets are laid along the undulating surface of the cooling channel. The chain is equipped with scrapers. The chain drive motor is located at both ends of the cooling channel and works in conjunction with the chain and sprockets to drive the scrapers to carry the slag through each cooling pool. The slag wastewater collection device includes a filter press connected to a water-sealed scraper slag discharge machine, which dewaters the slag. The wastewater supply device includes a circulating water tank, a PLC controller, several water pumps, and corresponding primary cooling tanks, secondary cooling tanks, ..., and final cooling tanks, with primary storage tanks, secondary storage tanks, ..., and final storage tanks. The circulating water tank receives circulating water from the plant area and slag recovery water obtained from the filter press. The circulating water tank is connected to the final storage tank by an inlet pipe. The inlet pipe of each cooling tank is connected to the corresponding storage tank, and the outlet pipe of each tank is connected to the storage tank of the next higher cooling tank. Each inlet and outlet pipeline is equipped with a water pump. Each water pump and each temperature sensor are connected to the PLC controller. The PLC controller controls the start and stop of each water pump according to the temperature of each pool, and drives the circulating water to finally converge in the primary cooling pool and evaporate completely. The generated steam rises and enters the secondary combustion chamber through the steam pipeline, and finally enters the flue gas treatment system.

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