A comprehensive hazardous waste treatment system and method

Abstract

The present invention relates to a comprehensive treatment system and method for hazardous wastes, and belongs to the field of hazardous waste treatment. The system includes a supercritical water gasification and oxidation system for treating high-water content wastes, a rotary kiln high-temperature incineration system for treating solid and semi-solid wastes, and a high-temperature plasma treatment system for treating no-calorific value and low-calorific value wastes; a hydrogen-rich fuel gas channel is connected from the supercritical water gasification and oxidation system to the rotary kiln high-temperature incineration system; a fly ash and residue channel is connected from the rotary kiln high-temperature incineration system to the high-temperature plasma treatment system; a deacidified wastewater channel is connected from the rotary kiln high-temperature incineration system to the supercritical water gasification and oxidation system; and a high-temperature flue gas channel is connected from the high-temperature plasma treatment system to the rotary kiln high-temperature incineration system. The supercritical water treatment, incineration treatment and high-temperature plasma treatment technologies are organically combined to solve the problem that a single technology is difficult to meet the requirements of comprehensive treatment of hazardous wastes, including resource utilization, reduction and harmlessness.

Description

Technical Field

[0001] The present invention belongs to the technical field of hazardous waste treatment, and relates to a comprehensive hazardous waste treatment system and method. Background Art

[0002] The technologies commonly used to treat hazardous wastes now include incineration technology, plasma treatment technology, and supercritical water treatment technology. The above three technologies have their own advantages and disadvantages, and they are suitable for slightly different treatment objects. Supercritical water treatment technology is suitable for treating high-water content wastes, especially organic wastes. When it is used to treat solid or semi-solid wastes with low water content, although it can be converted from low water content to high water content through dilution, after economic cost accounting, this technology is not the most suitable. Incineration technology can treat a wide range of hazardous wastes, and it is relatively mature, but when treating high-water content or low calorific value wastes, it is difficult to achieve reduction, resource utilization and harmless treatment through incineration technology. According to the current regulations of the Ministry of Environmental Protection, incineration residues, fly ash, and deacidified wastewater are still hazardous wastes and need to be safely landfilled or reprocessed. Plasma high-temperature treatment technology can completely transform hazardous waste into highly stable and harmless glassy slag, thereby realizing resource utilization. Especially when treating hazardous waste with no or low calorific value, it has advantages that other technologies cannot match. However, when treating waste with high calorific value or high volatility, it requires the same subsequent treatment system as incineration technology, and cannot treat waste with high moisture content.

[0003] As the amount and types of hazardous waste continue to increase, and as environmental protection requirements become increasingly stringent, a single hazardous waste treatment technology can no longer meet the comprehensive treatment requirements of hazardous waste resource utilization, reduction, and harmlessness. Moreover, when a single technology is used, improper disposal can easily cause secondary pollution. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a comprehensive treatment system and method for hazardous waste, so as to solve the problem that the use of incineration technology, plasma treatment technology and supercritical water treatment technology alone is difficult to meet the comprehensive treatment requirements of hazardous waste resource utilization, reduction and harmlessness.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A comprehensive treatment system for hazardous wastes comprises a supercritical water gasification and oxidation system for treating wastes with high water content, a rotary kiln high temperature incineration system for treating solid and semi-solid wastes, and a high temperature plasma treatment system for treating wastes with no calorific value or low calorific value; a hydrogen-rich fuel gas channel is connected from the supercritical water gasification and oxidation system to the rotary kiln high temperature incineration system; a fly ash and residue channel is connected from the rotary kiln high temperature incineration system to the high temperature plasma treatment system; a deacidified wastewater channel is connected from the rotary kiln high temperature incineration system to the supercritical water gasification and oxidation system; and a high temperature flue gas channel is connected from the high temperature plasma treatment system to the rotary kiln high temperature incineration system.

[0007] Furthermore, the supercritical water gasification and oxidation system includes a high-water content waste tank, a pretreatment device, a high-pressure pump, a supercritical water gasification and oxidation reaction device and a liquid-solid separation device which are connected in sequence; the liquid-solid separation device is respectively connected to a clean water tank pool and a resource-based residue bin.

[0008] Furthermore, a reflux channel is connected from the clean water tank pool to the high-water content waste tank bin, and the clean water tank pool is also provided with a drainage channel.

[0009] Furthermore, the rotary kiln high temperature incineration system includes a solid and semi-solid waste tank, a rotary kiln, a secondary combustion chamber, a waste heat boiler and a post-processing device which are connected in sequence; the hydrogen-rich fuel gas channel is connected to the rotary kiln and the secondary combustion chamber respectively from the supercritical water gasification and oxidation reaction device; the deacidified wastewater channel is connected to the high water content waste tank from the post-processing device.

[0010] Furthermore, the post-processing device is connected to an exhaust chimney.

[0011] Furthermore, the high-temperature plasma treatment system includes a non-calorific value and low-calorific value waste tank, a high-temperature plasma treatment device and a second resource-based residue bin which are connected in sequence; the fly ash and residue channels are connected to the high-temperature plasma treatment device from the secondary combustion chamber, the waste heat boiler and the post-treatment device respectively; the high-temperature flue gas channel is connected to the secondary combustion chamber from the high-temperature plasma treatment device.

[0012] A method for comprehensive treatment of hazardous wastes comprises the following steps:

[0013] Classification and storage: Hazardous wastes are classified into three categories for storage: high-water content wastes, solid and semi-solid wastes, and wastes with no calorific value and low calorific value;

[0014] Supercritical water treatment: high water content waste is treated through supercritical water gasification and oxidation system to obtain clean water and resource-based residues, while generating hydrogen-rich gas;

[0015] Incineration treatment: Solid and semi-solid wastes are treated through a rotary kiln high-temperature incineration system. At the same time, the hydrogen-rich gas generated during the supercritical water treatment process is used as fuel to reduce the generation of nitrogen oxides, thereby obtaining flue gas that meets emission standards. At the same time, the fly ash and residue generated are passed through a high-temperature plasma treatment system for treatment, and the deacidified wastewater generated is passed through a supercritical water gasification and oxidation system for pretreatment and conditioning of the supercritical water gasification and oxidation system and decomposition of organic matter in the deacidified wastewater;

[0016] Plasma treatment: The high-temperature plasma treatment system is used to treat wastes with no calorific value or low calorific value. At the same time, the fly ash and residues generated during the incineration process are received to obtain resource-based residues. At the same time, the high-temperature flue gas generated is introduced into the rotary kiln high-temperature incineration system.

[0017] Furthermore, in the supercritical water treatment step, the high-water content waste is pretreated and pressurized in sequence, and then introduced into a supercritical water gasification-oxidation reaction device for reaction. The reaction produces hydrogen-rich fuel gas, and the liquid and solid substances produced by the reaction are separated into clean water and resource-based residues, respectively.

[0018] Furthermore, the clean water obtained in the supercritical water treatment step is divided into two parts: one part is returned to the supercritical water gasification and oxidation system as reuse clean water to achieve water recycling; the other part is discharged as discharge clean water.

[0019] Furthermore, in the incineration treatment step, solid and semi-solid waste enters the rotary kiln for primary combustion, and then enters the secondary combustion chamber for secondary combustion. The high-temperature flue gas generated after combustion enters the waste heat boiler for heat recovery. After heat recovery, the product enters the post-treatment device for treatment, wherein the deacidified wastewater generated is passed into the supercritical water gasification and oxidation system, and the fly ash and residue are passed into the high-temperature plasma treatment system, and the flue gas that meets the emission standards is discharged; the hydrogen-rich fuel gas generated during the supercritical water treatment process is divided into two parts: one part is passed into the rotary kiln, and the other part is passed into the secondary combustion chamber.

[0020] The beneficial effects of the present invention are:

[0021] (1) The present invention realizes the reduction, harmlessness and resource treatment of hazardous wastes by organically combining supercritical water gasification and oxidation treatment technology, rotary kiln high temperature incineration technology and high temperature plasma treatment technology, and finally achieves zero emission. In addition, the comprehensiveness, adaptability and economy of hazardous waste treatment are improved.

[0022] (2) The present invention improves energy utilization and reduces the need for external energy by applying hydrogen-rich gas generated by supercritical water treatment and high-temperature flue gas generated by plasma treatment to incineration treatment. By using hydrogen-rich gas generated by supercritical water treatment in incineration treatment, the overall carbon-hydrogen ratio of the gas is reduced, thereby reducing the generation of nitrogen oxides, thereby enhancing energy saving, economy and environmental protection.

[0023] (3) The present invention not only pre-treats and conditions the deacidified wastewater generated by incineration treatment by passing it into a supercritical water gasification and oxidation system, but also uses the supercritical water gasification and oxidation system to thoroughly treat the organic matter in the deacidified wastewater, thereby achieving a harmless treatment effect and avoiding secondary pollution. The high-temperature plasma treatment system is used to achieve harmless and resourceful disposal of the residues and fly ash generated during incineration treatment, ultimately avoiding secondary pollution.

[0024] (4) The present invention reduces the subsequent equipment of the high-temperature plasma treatment system by using the high-temperature flue gas of the high-temperature plasma treatment system in the rotary kiln high-temperature incineration system, thereby simplifying the system and making the equipment more compact.

[0025] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 This is a schematic diagram of the layout of a comprehensive hazardous waste treatment system of the present invention.

[0028] Figure numerals: high-water content waste tank 1, pretreatment device 2, high-pressure pump 3, supercritical water gasification and oxidation reaction device 4, liquid-solid material 5, hydrogen-rich fuel gas 6, clean water 7, resource-based residue 8, liquid-solid separation device 9, clean water tank pool 10, resource-based residue bin 11, solid and semi-solid waste tank 12, rotary kiln 13, secondary combustion chamber 14, waste heat boiler 15, after-products of heat recovery from combustion 16, post-treatment device 17, waste heat boiler residue 18, fly ash and residue 19, emission chimney 20, no calorific value and low calorific value waste tank 21, high-temperature plasma treatment device 22, secondary combustion chamber residue 23, resource-based residue bin 2 24, plasma resource-based residue 25, deacidified wastewater 26, emission clean water 27, reused clean water 28. DETAILED DESCRIPTION

[0029] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0030] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0031] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] See also Figure 1 It is a comprehensive hazardous waste treatment system, including a supercritical water gasification and oxidation system for treating high-water content waste, a rotary kiln high-temperature incineration system for treating solid and semi-solid waste, and a high-temperature plasma treatment system for treating no-calorific value and low-calorific value waste.

[0033] Specifically, the supercritical water gasification and oxidation system includes a high-water content waste tank 1, a pretreatment device 2, a high-pressure pump 3, a supercritical water gasification and oxidation reaction device 4 and a liquid-solid separation device 9 which are connected in sequence; the liquid-solid separation device 9 is respectively connected to a clean water tank pool 10 and a resource-based residue bin 11. A reflux channel is connected from the clean water tank pool 10 to the high-water content waste tank 1, and the clean water tank pool 10 is also provided with a drainage channel.

[0034] The rotary kiln high temperature incineration system includes a solid and semi-solid waste tank 12, a rotary kiln 13, a secondary combustion chamber 14, a waste heat boiler 15 and a post-processing device 17 which are connected in sequence. The post-processing device 17 is connected to an emission chimney 20; a hydrogen-rich fuel gas channel is connected to the rotary kiln 13 and the secondary combustion chamber 14 from a supercritical water gasification and oxidation reaction device 4 respectively; a deacidified wastewater channel is connected to the high-water content waste tank 1 from the post-processing device 17.

[0035] The high-temperature plasma treatment system includes a non-calorific value and low-calorific value waste tank 21, a high-temperature plasma treatment device 22 and a resource-based residue bin 24 which are connected in sequence; fly ash and residue channels are connected to the high-temperature plasma treatment device 22 from the secondary combustion chamber 14, the waste heat boiler 15 and the post-treatment device 17 respectively; and a high-temperature flue gas channel is connected to the secondary combustion chamber 14 from the high-temperature plasma treatment device 22.

[0036] This embodiment also provides a method for comprehensive treatment of hazardous wastes, comprising the following steps:

[0037] Classification and storage: Hazardous wastes are classified into three categories: high-water content wastes, solid and semi-solid wastes, and wastes with no calorific value and low calorific value, and stored in corresponding tanks;

[0038] Supercritical water treatment: The high-water-content waste in the high-water-content waste tank 1 is pretreated by the pretreatment device 2, and the pressure is increased by the high-pressure pump 3, and then introduced into the supercritical water gasification and oxidation reaction device 4 for reaction. The hydrogen-rich fuel gas 6 produced by the reaction enters the rotary kiln high-temperature incineration system for use. The liquid-solid substance 5 produced by the reaction is separated into liquid and solid by the liquid-solid separation device 9, and the resource residue 8 is obtained in the resource residue bin 11 for subsequent resource use. Clean water 7 is obtained in the clean water tank pool 10, a part of which is returned to the high-water-content waste tank 1 through the reflux channel as the reused clean water 28 to realize water recycling, and the other part is discharged through the drainage channel as the discharged clean water 27;

[0039] Incineration treatment: the solid and semi-solid waste in the solid and semi-solid waste tank 12 is pre-treated and introduced into the rotary kiln 13 for primary combustion, and then introduced into the secondary combustion chamber 14 for secondary combustion. The high-temperature flue gas generated after combustion enters the waste heat boiler 15 for heat recovery. After heat recovery, the product 16 enters the post-treatment device 17 for treatment, wherein the deacidified waste water 26 generated enters the high-water content waste tank 1 through the deacidified waste water channel, which is not only used for pretreatment and tempering of the supercritical water gasification and oxidation system, but also decomposes the organic matter in the deacidified waste water 26, and the flue gas that meets the emission standards is discharged through the emission chimney 20; the hydrogen-rich fuel gas 6 generated by the supercritical water gasification and oxidation reaction device 4 is divided into two parts: one part is introduced into the rotary kiln 13, and the other part is introduced into the secondary combustion chamber 14.

[0040] Plasma treatment: The wastes with no calorific value and low calorific value in the waste tank 21 with no calorific value and low calorific value are introduced into the high-temperature plasma treatment device 22 for treatment, and the secondary combustion chamber residue 23 generated by the secondary combustion chamber 14, the waste heat boiler residue 18 generated by the waste heat boiler 15, and the fly ash and residue 19 generated by the post-treatment device 17 are introduced into the high-temperature plasma treatment device 22 through the fly ash and residue channels for treatment, and the plasma resource residue 25 is obtained in the resource residue bin 24 for subsequent resource utilization; the high-temperature flue gas generated by the high-temperature plasma treatment device 22 enters the secondary combustion chamber 14 through the high-temperature flue gas channel for combustion utilization.

[0041] By organically combining supercritical water gasification and oxidation treatment technology, rotary kiln high-temperature incineration technology and high-temperature plasma treatment technology, we can achieve the reduction, harmlessness and resource treatment of hazardous wastes, and ultimately achieve zero emissions. In addition, we can improve the comprehensiveness, adaptability and economy of hazardous waste treatment.

[0042] By using hydrogen-rich gas 6 produced by supercritical water treatment and high-temperature flue gas produced by plasma treatment in incineration, energy utilization can be improved and the demand for purchased energy can be reduced. By using hydrogen-rich gas 6 produced by supercritical water treatment in incineration, the overall carbon-hydrogen ratio of the gas is reduced, thereby reducing the generation of nitrogen oxides, enhancing energy saving, economy and environmental protection.

[0043] By passing the deacidified wastewater 26 generated by incineration into the supercritical water gasification and oxidation system, not only the supercritical water gasification and oxidation treatment system is pre-treated and tempered, but also the organic matter in the deacidified wastewater 26 is thoroughly treated by the supercritical water gasification and oxidation system to achieve a harmless treatment effect and avoid secondary pollution. The high-temperature plasma treatment system is used to achieve harmless and resourceful disposal of the residues and fly ash generated in the incineration treatment, ultimately avoiding secondary pollution.

[0044] By using the high temperature flue gas of the high temperature plasma treatment system in the rotary kiln high temperature incineration system, the subsequent equipment of the high temperature plasma treatment system is reduced, thereby simplifying the system and making the equipment more compact.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A comprehensive hazardous waste treatment system, characterized by: It includes a supercritical water gasification and oxidation system for treating wastes with high water content, a rotary kiln high temperature incineration system for treating solid and semi-solid wastes, and a high temperature plasma treatment system for treating wastes with no calorific value and low calorific value; a hydrogen-rich fuel gas channel is connected from the supercritical water gasification and oxidation system to the rotary kiln high temperature incineration system; a fly ash and residue channel is connected from the rotary kiln high temperature incineration system to the high temperature plasma treatment system; a deacidified wastewater channel is connected from the rotary kiln high temperature incineration system to the supercritical water gasification and oxidation system; and a high temperature flue gas channel is connected from the high temperature plasma treatment system to the rotary kiln high temperature incineration system; The supercritical water gasification and oxidation system comprises a high-water content waste tank, a pretreatment device, a high-pressure pump, a supercritical water gasification and oxidation reaction device and a liquid-solid separation device which are connected in sequence; the liquid-solid separation device is respectively connected to a clean water tank pool and a resource-based residue tank one; A reflux channel is connected from the clean water tank pool to the high water content waste tank bin, and the clean water tank pool is also provided with a drainage channel; The rotary kiln high temperature incineration system comprises a solid and semi-solid waste tank, a rotary kiln, a secondary combustion chamber, a waste heat boiler and a post-processing device which are connected in sequence; the hydrogen-rich fuel gas channel is connected to the rotary kiln and the secondary combustion chamber respectively from the supercritical water gasification and oxidation reaction device; the deacidified wastewater channel is connected to the high water content waste tank from the post-processing device; The high-temperature plasma treatment system includes a non-calorific value and low-calorific value waste tank, a high-temperature plasma treatment device and a second resource-based residue tank connected in sequence; the fly ash and residue channels are connected to the high-temperature plasma treatment device from the secondary combustion chamber, the waste heat boiler and the post-treatment device respectively; the high-temperature flue gas channel is connected to the secondary combustion chamber from the high-temperature plasma treatment device.

2. The comprehensive hazardous waste treatment system according to claim 1 is characterized by: The post-processing device is connected to an exhaust chimney.

3. A method for comprehensive treatment of hazardous wastes based on the comprehensive treatment system for hazardous wastes according to claim 1 or 2, characterized in that: The following steps are involved: Classification and storage: Hazardous wastes are classified into three categories for storage: high-water content wastes, solid and semi-solid wastes, and wastes with no calorific value and low calorific value; Supercritical water treatment: high water content waste is treated through supercritical water gasification and oxidation system to obtain clean water and resource-based residues, while generating hydrogen-rich gas; Incineration treatment: Solid and semi-solid wastes are treated through a rotary kiln high-temperature incineration system. At the same time, the hydrogen-rich gas generated during the supercritical water treatment process is used as fuel to reduce the generation of nitrogen oxides, thereby obtaining flue gas that meets emission standards. At the same time, the fly ash and residue generated are passed through a high-temperature plasma treatment system for treatment, and the deacidified wastewater generated is passed through a supercritical water gasification and oxidation system for pretreatment and conditioning of the supercritical water gasification and oxidation system and decomposition of organic matter in the deacidified wastewater; Plasma treatment: The high-temperature plasma treatment system is used to treat wastes with no calorific value or low calorific value. At the same time, the fly ash and residues generated during the incineration process are received to obtain resource-based residues. At the same time, the high-temperature flue gas generated is introduced into the rotary kiln high-temperature incineration system.

4. The method for comprehensive treatment of hazardous wastes according to claim 3, characterized in that: In the supercritical water treatment step, the high-water content waste is pretreated and pressurized in sequence, and then introduced into a supercritical water gasification and oxidation reaction device for reaction. The reaction produces hydrogen-rich fuel gas, and the liquid and solid substances produced by the reaction are separated into clean water and resource-based residues.

5. The method for comprehensive treatment of hazardous wastes according to claim 3, characterized in that: The clean water obtained in the supercritical water treatment step is divided into two parts: one part is returned to the supercritical water gasification and oxidation system as recycled clean water to achieve water recycling; the other part is discharged as discharged clean water.

6. The method for comprehensive treatment of hazardous wastes according to claim 3, characterized in that: In the incineration treatment step, solid and semi-solid waste enters the rotary kiln for primary combustion, and then enters the secondary combustion chamber for secondary combustion. The high-temperature flue gas generated after combustion enters the waste heat boiler for heat recovery. After the heat is recovered, the product enters the post-treatment device for treatment, wherein the deacidified wastewater generated is passed into the supercritical water gasification and oxidation system, the fly ash and residue are passed into the high-temperature plasma treatment system, and the flue gas that meets the emission standards is discharged; the hydrogen-rich fuel gas generated during the supercritical water treatment process is divided into two parts: one part is passed into the rotary kiln, and the other part is passed into the secondary combustion chamber.

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