Waste incineration fly ash treatment system and method

Abstract

The present invention relates to the technical field of waste treatment and recycling, and discloses a waste incineration fly ash treatment system and method. The fly ash treatment system comprises a segmented rotary kiln and an oxygen-free feeder, the segmented rotary kiln comprises a first heating section, a second heating section and a third heating section which are connected in sequence, the oxygen-free feeder is connected to the first heating section, a first reducing agent feeder is provided at the first heating section near the oxygen-free feeder, a low-melting-point metal recoverer is provided at the end of the first heating section near the second heating section; a salt recoverer is provided at the end of the second heating section near the third heating section; a second reducing agent feeder is provided at the third heating section near the second heating section, and a heavy metal recoverer is provided at the end of the third heating section away from the second heating section. The fly ash treatment method adopts the treatment system provided by the present invention to treat the fly ash generated by the domestic waste incineration power plant. The present application can recover metals, salts and heavy metals in the fly ash, and the detoxified fly ash can be used as environmentally friendly aggregate.

Description

Technical Field

[0001] The present invention relates to the technical field of waste treatment and recycling, and in particular to a waste incineration fly ash treatment system and method. Background Art

[0002] Waste incineration is the process of reducing the volume of waste by oxidation at high temperature through appropriate thermal decomposition, combustion, melting and other reactions, and turning it into residue or molten solid matter. In order to utilize the heat generated by incineration of waste, the heat generated by waste incineration is currently usually used to generate electricity.

[0003] The fly ash from waste incineration power plants contains many substances that are harmful to the environment. Researchers conducted a particle size classification toxicity analysis on the fly ash from a waste incineration power plant. The main research was on the corrosiveness and short-term leaching toxicity of fly ash with a particle size range of 35 to 1 000 μm. The results showed that heavy metals including Cr, Cd, Mg, Pb, Mn, Fe, Cu, Zn, Ni, Co, SO 2 4- , Cl - , NO 3 —N and NO 2 —N. The material composition and mineral characteristics of fly ash were also studied. The results showed that the pH value of the leachate of fly ash of all particle sizes was between 12.3 and 12.5, which was a corrosive hazardous waste. The leaching concentrations of heavy metals Mg, Pb, and Zn were the highest, at 168.78, 53.94, and 86.40 mg / L, respectively. The highest leachate and content of fly ash reached 8.87 g / L and 1.38 g / L, respectively. At the same time, a certain amount of nitrate nitrogen and nitrite nitrogen were measured in the leachate, proving that fly ash adsorbed nitrogen oxide gas produced during the incineration process. In addition, the study concluded that the basic components of fly ash are Ca, Si, Cl, K, Na, S, Al, Mg, and Fe, while the heavy metals are mainly Zn, Pb, Mn, Cu, Cr, etc. The mineral phase is mainly silicon- and calcium-containing compounds and chlorides such as NaCl and KCl.

[0004] Based on the above research results, it can be seen that if the fly ash can be treated, the useful substances in it can be recovered, and its toxicity can be reduced, the valuable utilization of fly ash can be achieved and economic benefits can be achieved.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The purpose of the present invention includes, for example, providing a waste incineration fly ash treatment system and method, which can treat the fly ash and realize resource recycling.

[0007] The embodiments of the present invention can be implemented as follows:

[0008] In a first aspect, the present invention provides a waste incineration fly ash treatment system, comprising a segmented rotary kiln and an oxygen-free feeder.

[0009] The segmented rotary kiln includes a first heating section, a second heating section and a third heating section which are connected in sequence. The oxygen-free feeder is connected to the first heating section. A first reducing agent feeder is provided at the first heating section near the oxygen-free feeder, and a low-melting-point metal recoverer is provided at the end of the first heating section near the second heating section; a salt recoverer is provided at the end of the second heating section near the third heating section; a second reducing agent feeder is provided at the third heating section near the second heating section, and a heavy metal recoverer is provided at the end of the third heating section away from the second heating section.

[0010] In an optional embodiment, the waste incineration fly ash treatment system further includes a storage box and a cooling system, an end of the third heating section away from the second heating section is connected to the storage box, and the cooling system is connected to the lower part of the storage box.

[0011] In an optional embodiment, the waste incineration fly ash treatment system further includes an anaerobic discharger, which is connected to the discharge end of the cooling system.

[0012] In an optional embodiment, the waste incineration fly ash treatment system further includes a storage box, and the upper portion of the storage box is connected to the dust collector.

[0013] In an optional embodiment, the waste incineration fly ash treatment system further includes a gas treatment system connected to the dust collector.

[0014] In an optional embodiment, the gas treatment system includes a gas water scrubber, and a gas outlet of the gas water scrubber is sequentially connected to a gas condenser, a supersonic processor, a photo-oxygen processor, a plasma processor, and an electrostatic processor.

[0015] In an optional embodiment, the wash liquid outlet of the gas water scrubber is sequentially connected to a filter, an electrolytic cell and a salt recovery system.

[0016] In a second aspect, the present invention provides a method for treating fly ash from waste incineration, wherein the fly ash generated by a municipal waste incineration power plant is treated by a waste incineration fly ash treatment system as described in any of the aforementioned embodiments, the heating temperature of the first heating section is 310-330°C, the heating temperature of the second heating section is 850-950°C, and the heating temperature of the third heating section is 1150-1250°C.

[0017] In an optional embodiment, the heating temperature of the first heating section is 315-325°C, the heating temperature of the second heating section is 890-910°C, and the heating temperature of the third heating section is 1180-1220°C.

[0018] In an optional embodiment, the reducing agent added to the first reducing agent feeder includes activated carbon.

[0019] The beneficial effects of the embodiments of the present invention include, for example:

[0020] The waste incineration fly ash treatment system, due to the segmented heating setting of the segmented rotary kiln, and the specific setting of the oxygen-free feeder and each recycler, enables the treatment system to recover metals, salts and heavy metals in the fly ash after setting reasonable heating temperatures in each heating section of the segmented heating furnace, remove or greatly reduce the toxicity of the fly ash, and the reduced toxicity fly ash can be used as environmentally friendly aggregate. The system can realize the reuse of waste and generate economic value.

[0021] The method for treating fly ash from waste incineration adopts the waste incineration fly ash treatment system provided by the present invention to treat fly ash, and sets the heating temperature of the first heating section to 320-330°C, the heating temperature of the second heating section to 850-950°C, and the heating temperature of the third heating section to 1150-1250°C. This can realize the recovery of metals, salts and heavy metals in the ash, remove or greatly reduce the toxicity of the fly ash, and the attenuated fly ash can be used as environmentally friendly aggregate to achieve the reuse of incineration ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic diagram of the structure of a fly ash treatment system provided by an embodiment of the present invention;

[0024] Figure 2 A schematic structural diagram of a gas treatment system of a fly ash treatment system provided in an embodiment of the present invention.

[0025] Icons: 100-fly ash treatment system; 101-fly ash closed storage box; 110-segmented rotary kiln; 111-first heating section; 112-second heating section; 113-third heating section; 114-first reducing agent adder; 115-second reducing agent adder; 116-low melting point metal recoverer; 117-salt recoverer; 118-heavy metal recoverer; 120-oxygen-free feeder; 130-storage box; 140-cooling system; 150-oxygen-free discharger; 160-dust collector; 170-gas treatment system; 171-gas water scrubber; 172-gas condenser; 173-supersonic processor; 174-photooxygen processor; 175-plasma processor; 176-electrostatic processor; 177-filter; 178-electrolytic cell; 179-salt recovery system. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0031] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0032] Please refer to Figure 1 and Figure 2 As shown, this embodiment provides a waste incineration fly ash treatment system 100, including a segmented rotary kiln 110 and an oxygen-free feeder 120.

[0033] The segmented rotary kiln 110 includes a first heating section 111, a second heating section 112 and a third heating section 113 which are connected in sequence. The oxygen-free feeder 120 is connected to the first heating section 111. A first reducing agent injector 114 is provided at the first heating section 111 near the oxygen-free feeder 120, and a low-melting-point metal recoverer 116 is provided at the end of the first heating section 111 near the second heating section 112; a salt recoverer 117 is provided at the end of the second heating section 112 near the third heating section 113; a second reducing agent injector 115 is provided at the third heating section 113 near the second heating section 112, and a heavy metal recoverer 118 is provided at the end of the third heating section 113 away from the second heating section 112.

[0034] The fly ash generated by the municipal solid waste incineration power plant is stored in a fly ash sealed storage box 101, which is connected to the oxygen-free feeder 120. The fly ash is continuously fed into the segmented rotary kiln 110 under the action of the oxygen-free feeder 120. The heating temperature of the first heating section 111 is controlled to be 310-330°C, the heating temperature of the second heating section 112 is controlled to be 850-950°C, and the heating temperature of the third heating section 113 is controlled to be 1150-1250°C. When the fly ash enters the first heating section 111, the low melting point metal in the fly ash is reduced under the action of the reducing agent added by the first reducing agent feeder 114, and the low melting point metal such as tin and lead is melted into liquid and recovered by the low melting point metal recoverer 116. After the fly ash enters the second heating section 112, most of the salt in the fly ash begins to melt, and the liquid salt is recovered by the salt recoverer 117. After the fly ash enters the third heating section 113 , the heavy metals are reduced under the action of the heavy metal reducing agent added by the second reducing agent adder 115 , and then melted into liquid at high temperature, and finally recovered by the heavy metal recoverer 118 .

[0035] The fly ash generated by the municipal solid waste incineration power plant is treated by the waste incineration fly ash treatment system provided in this embodiment, and the metals and salts therein are recovered, and its toxicity is reduced. The treated fly ash can also be used as environmentally friendly aggregate to achieve resource recycling.

[0036] The above-mentioned reducer feeders are all oxygen-free feeders 120; the low melting point metal recoverer 116, the salt recoverer 117 and the heavy metal recoverer 118 are structures that can be installed on the furnace body to collect the liquid generated during the heating process. The reducing agent added to the first reducing agent feeder 114 and the second reducing agent feeder 115 is activated carbon.

[0037] Furthermore, the waste incineration fly ash treatment system also includes a storage box 130 and a cooling system 140 . An end of the third heating section 113 away from the second heating section 112 is connected to the storage box 130 , and the cooling system 140 is connected to the lower part of the storage box 130 .

[0038] The cooling system 140 cools the high-temperature fly ash produced by the staged rotary furnace 110 to room temperature.

[0039] In this embodiment, the cooling system 140 may cool the processed fly ash in a water-cooling manner. The cooling water of the cooling system 140 acts as a cold source to reduce the temperature of the fly ash during the process of cooling the fly ash, while the cooling water of the cooling system 140 increases its own temperature.

[0040] Preferably, the waste incineration fly ash treatment system further includes an anaerobic discharger 150 , which is connected to the discharge end of the cooling system 140 .

[0041] The fly ash cooled to room temperature is discharged by the oxygen-free discharger 150. The oxygen-free discharger 150 can prevent oxygen from entering the staged rotary kiln 110 during the discharge process to affect the treatment effect. The discharged treated fly ash has salt and metals basically removed, and can be used as environmentally friendly aggregate to achieve resource recycling.

[0042] Furthermore, the waste incineration fly ash treatment system also includes a storage box 130 , and the upper part of the storage box 130 is connected to the dust collector 160 .

[0043] The processed fly ash is discharged by the dust collector 160 , and the solid remains in the storage box 130 .

[0044] Furthermore, the waste incineration fly ash treatment system also includes a gas treatment system 170 connected to the dust collector 160 .

[0045] The gas discharged from the storage box 130 contains sulfur-containing gas, nitrogen-containing gas and other gases that are harmful to the environment. Therefore, it needs to be processed by the gas processing system 170 before being discharged into the atmosphere.

[0046] Preferably, the gas treatment system 170 includes a gas water scrubber 171 , and a gas outlet of the gas water scrubber 171 is sequentially connected to a gas condenser 172 , a supersonic processor 173 , a photo-oxygen processor 174 , a plasma processor 175 and an electrostatic processor 176 .

[0047] The high-temperature gas is washed by a water washing tower to remove sulfur, nitrogen and other substances in the gas; the gas after water washing is rapidly cooled down by a gas condenser 172 (to below 200°C within 2 seconds) to prevent the decomposed dioxins from being synthesized again; the cooled gas enters a supersonic processor 173 to remove moisture, oil and other substances contained therein; then the gas enters a photo-oxygen processor 174, which performs photo-oxygen catalytic treatment; then the gas enters a plasma processor 175 for plasma treatment; finally, the gas enters an electrostatic processor 176 for electrostatic treatment; harmful substances in the gas after electrostatic treatment are basically removed, and the gas meets the emission standards.

[0048] Preferably, the washing liquid outlet of the gas washing tower 171 is connected to the filter 177, the electrolytic cell 178 and the salt recovery system 179 in sequence.

[0049] The washing liquid of the water washing tower adsorbs soluble harmful substances in the gas discharged from the segmented rotary kiln 110, so it needs to be treated before it can be discharged or reused. The washing liquid is filtered by the filter 177 to remove impurities and then enters the electrolytic cell 178, where heavy metals that may exist are electrolyzed to remove them. The water treated by the electrolytic cell 178 then enters the salt recovery system 179 for desalination and softening. The water treated by the salt recovery system 179 meets the discharge requirements.

[0050] Preferably, the drain outlet of the salt recovery system 179 is in communication with the condensate inlet of the cooling system 140 .

[0051] The treated water that meets the standards can be used as condensed water for the cooling system 140, thereby realizing resource recycling.

[0052] The embodiment of the present application also provides a method for treating fly ash from waste incineration. The fly ash generated by a municipal waste incineration power plant is treated using the waste incineration fly ash treatment system provided in the embodiment of the present application. The heating temperature of the first heating section 111 is 320-330°C, the heating temperature of the second heating section 112 is 850-950°C, and the heating temperature of the third heating section 113 is 1150-1250°C.

[0053] Preferably, the heating temperature of the first heating section 111 is 315-325° C., the heating temperature of the second heating section 112 is 890-910° C., and the heating temperature of the third heating section 113 is 1180-1220° C. Further, the heating temperature of the first heating section 111 is generally controlled to be 320° C., the heating temperature of the second heating section 112 is 900° C., and the heating temperature of the third heating section 113 is 1200° C.

[0054] The fly ash is continuously fed into the segmented rotary kiln 110 under the action of the oxygen-free feeder 120. When the fly ash enters the first heating section 111, the low melting point metals in the fly ash are reduced under the action of the reducing agent added by the first reducing agent feeder 114, and the low melting point metals such as tin and lead are melted into liquid state and recovered by the low melting point metal recoverer 116. After the fly ash enters the second heating section 112, most of the salt in the fly ash begins to melt, and the liquid salt is recovered by the salt recoverer 117. After the fly ash enters the third heating section 113, the heavy metals are reduced under the action of the heavy metal reducing agent added by the second reducing agent feeder 115, and then melted into liquid state at high temperature, and finally recovered by the heavy metal recoverer 118.

[0055] Further preferably, the reducing agent added to the first reducing agent feeder 114 and the second reducing agent feeder 115 includes activated carbon for reducing metal ions in the fly ash. The heavy metal reducing agent added to the second reducing agent feeder 115 is used to reduce heavy metal ions in the fly ash.

[0056] In summary, the waste incineration fly ash treatment system provided by the present invention, due to the segmented heating setting of the segmented rotary kiln, and in combination with the specific setting of the oxygen-free feeder and each recycler, enables the treatment system to recover metals, salts and heavy metals in the fly ash after setting a reasonable heating temperature in each heating section of the segmented heating furnace, remove or greatly reduce the toxicity of the fly ash, and the attenuated fly ash can be used as environmentally friendly aggregate. The system can realize the reuse of waste and generate economic value.

[0057] The waste incineration fly ash treatment method provided by the present invention adopts the waste incineration fly ash treatment system provided by the present invention to treat the fly ash, and the heating temperature of the first heating section is set to 320-330°C, the heating temperature of the second heating section is set to 850-950°C, and the heating temperature of the third heating section is set to 1150-1250°C, so that the metals, salts and heavy metals in the ash can be recovered, the toxicity of the fly ash can be removed or greatly reduced, and the attenuated fly ash can be used as environmentally friendly aggregate to achieve the reuse of incineration ash.

[0058] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for treating fly ash from waste incineration, characterized in that: The waste incineration fly ash treatment system is used to treat the fly ash generated by the domestic waste incineration power plant. The waste incineration fly ash treatment system includes a segmented rotary kiln and an oxygen-free feeder. The segmented rotary kiln comprises a first heating section, a second heating section and a third heating section which are connected in sequence, the oxygen-free feeder is connected to the first heating section, a first reducing agent feeder is provided at the first heating section near the oxygen-free feeder, a low-melting-point metal recoverer is provided at the end of the first heating section near the second heating section; a salt recoverer is provided at the end of the second heating section near the third heating section; a second reducing agent feeder is provided at the third heating section near the second heating section, and a heavy metal recoverer is provided at the end of the third heating section away from the second heating section; The heating temperature of the first heating section is 310-330°C, the heating temperature of the second heating section is 850-950°C, and the heating temperature of the third heating section is 1150-1250°C.

2. The method for treating fly ash from waste incineration according to claim 1, characterized in that: The waste incineration fly ash treatment system also includes a storage box and a cooling system. The end of the third heating section away from the second heating section is connected to the storage box, and the cooling system is connected to the lower part of the storage box.

3. The method for treating fly ash from waste incineration according to claim 2, characterized in that: The waste incineration fly ash treatment system also includes an anaerobic discharger, which is connected to the discharge end of the cooling system.

4. The method for treating fly ash from waste incineration according to any one of claims 1 to 3, characterized in that: The waste incineration fly ash treatment system also includes a storage box, and the upper part of the storage box is connected to the dust collector.

5. The method for treating fly ash from waste incineration according to claim 4, characterized in that: The waste incineration fly ash treatment system also includes a gas treatment system connected to the dust collector.

6. The method for treating fly ash from waste incineration according to claim 5, characterized in that: The gas treatment system comprises a gas water washing tower, and the gas outlet of the gas water washing tower is connected to a gas condenser, a supersonic processor, a photo-oxygen processor, a plasma processor and an electrostatic processor in sequence.

7. The method for treating fly ash from waste incineration according to claim 6, characterized in that: The washing liquid outlet of the gas washing tower is connected to the filter, the electrolytic cell and the salt recovery system in sequence.

8. The method for treating fly ash from waste incineration according to claim 1, characterized in that: The heating temperature of the first heating section is 315-325°C, the heating temperature of the second heating section is 890-910°C, and the heating temperature of the third heating section is 1180-1220°C.

9. The method for treating fly ash from waste incineration according to claim 8, characterized in that: The reducing agent added into the first reducing agent feeder includes activated carbon.

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