Double-layer combined device for drying and pyrolyzing waste salt

Abstract

The invention discloses a waste salt drying and pyrolyzing double-layer combined device which comprises a waste salt feeding system, a microwave drying furnace, a microwave pyrolyzing furnace, a pyrolyzing waste salt bin, a cooling system, a tail gas collecting system, a control system and the like. The waste salt feeding system is sequentially provided with a raw material waste salt bin and a feeding hopper elevator; waste salt in the raw material waste salt bin is conveyed to a feed port of the microwave drying furnace through the feed hopper elevator; the microwave drying furnace is located on a second-layer platform, a plate chain conveyor is arranged in the drying furnace, and waste salt entering from a feeding port moves forwards to an outlet of the microwave drying furnace through the plate chain conveyor and then falls into the microwave pyrolyzing furnace; the microwave pyrolyzing furnace is located on a first-layer platform, and a feeding port of the microwave pyrolyzing furnace is communicated with a discharging port of the microwave drying furnace through a vertical pipeline. A discharge port of the microwave pyrolyzing furnace is connected with a feed port of a discharge screw conveyor, a discharge port of the discharge screw conveyor is connected with a feed port of a pyrolyzing waste salt bin, and the waste salt is fed into the pyrolyzing waste salt bin and then enters a subsequent system to be treated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waste salt pyrolysis disposal, and particularly relates to a waste salt drying and pyrolysis double-layer combined device. BACKGROUND

[0002] Most of the high-salinity wastewater in the medical, chemical and other industries is treated by evaporation crystallization, forming a large amount of hazardous waste mixed salt containing organic matter, and its output is increasing year by year. The regulations such as the Hazardous Waste Landfill Pollution Control Standard (GB 18598-2019) clearly stipulate that when industrial waste salt is disposed of by flexible landfill method, the total amount of water-soluble salt must be less than 10% (mass fraction); and when industrial waste salt is disposed of by rigid landfill method, the cost will be significantly increased. When waste salt is treated by incineration, the waste salt containing organic matter is easy to melt and coking at high incineration temperature, which corrodes the furnace equipment and causes the system to be unable to run stably for a long time. At the same time, the waste salt contains a certain amount of moisture, and direct pyrolysis also increases the energy consumption of the equipment, affecting the economy of the overall system.

[0003] Therefore, based on the above problems, the application provides a waste salt drying and pyrolysis double-layer combined device. SUMMARY

[0004] The purpose of the application is to overcome the deficiencies in the prior art, provide a waste salt drying and pyrolysis double-layer combined device, which can not only effectively remove the moisture and TOC in the waste salt to meet the requirements of subsequent harmless disposal of waste salt, but also save the land occupation and reduce the overall operating energy consumption.

[0005] The purpose of the application is achieved by the following technical solutions: A waste salt drying and pyrolysis double-layer combined device, which comprises a waste salt feeding system, a microwave drying furnace, a microwave pyrolysis furnace, a pyrolysis waste salt bin, a cooling system, a tail gas collection system and a control system.

[0006] The waste salt feeding system is sequentially provided with a raw material waste salt bin and a feeding hopper elevator; the waste salt in the raw material waste salt bin is conveyed to the feeding port of the microwave drying furnace through the feeding hopper elevator; the microwave drying furnace is located on the second floor, and a plate chain conveyor is arranged in the drying furnace; the waste salt entering from the feeding port moves forward to the outlet of the microwave drying furnace through the plate chain conveyor and then falls into the microwave pyrolysis furnace; the microwave pyrolysis furnace is located on the first floor, and the feeding port of the microwave pyrolysis furnace is communicated with the discharging port of the microwave drying furnace through a vertical pipeline; the discharging port of the microwave pyrolysis furnace is connected with the feeding port of a discharging screw conveyor, and the discharging port of the discharging screw conveyor is connected with the feeding port of the pyrolysis waste salt bin, so that the waste salt is sent into the pyrolysis waste salt bin and then into the subsequent system for disposal.

[0007] Further, the waste salt drying and pyrolysis double-layer combined device is used for drying and pyrolysis disposal of various industrial waste salts and is suitable for mixed salt with a water content of not more than 15% and a TOC of not more than 5%.

[0008] Further, a waste salt drying and pyrolysis double-layer combined device adopts an upper and lower two-layer structure to arrange a microwave drying furnace and a microwave pyrolysis furnace; the microwave drying furnace is arranged on a two-layer platform and located directly above the microwave pyrolysis furnace; a feeding port of the microwave drying furnace is located on one side and opens upward to receive waste salt from a raw material bin; a discharging port of the microwave drying furnace is located on the other side and opens downward; a feeding port of the microwave pyrolysis furnace is located on one side and opens upward and is opposite to the discharging port of the microwave drying furnace and is connected and sealed by a pipeline; a discharging port of the microwave pyrolysis furnace is located on the other side and opens downward and discharges into a pyrolysis waste salt bin.

[0009] Further, a waste salt drying and pyrolysis double-layer combined device is completely sealed and transported except for a raw material waste salt bin feeding port and a pyrolysis waste salt bin discharging port; and a heat preservation layer is arranged outside the device body and the pipeline.

[0010] Further, a waste salt drying and pyrolysis double-layer combined device is provided with a nitrogen protection gas path inlet near a discharging port of the microwave pyrolysis furnace (similar to the tail gas discharge port) and is connected with a nitrogen protection system and is used for internal atmosphere protection of the device.

[0011] Further, a waste salt drying and pyrolysis double-layer combined device is provided with a tail gas collection system including a tail gas fan and is used for tail gas collection in the system; specifically, a tail gas discharge port is arranged near a feeding port of the microwave drying furnace; the tail gas discharge port is connected with the tail gas fan at the top end and is used for internal tail gas extraction of the device to ensure that the microwave furnace is operated in a micro-negative pressure state.

[0012] Further, a waste salt drying and pyrolysis double-layer combined device is provided with thermocouples on the microwave drying furnace and the microwave pyrolysis furnace respectively and is used for temperature monitoring; temperature data of the material is collected through a temperature control system and is used for real-time adjustment of the output power of the microwave generator by the control system to perform temperature control operation.

[0013] Further, a waste salt drying and pyrolysis double-layer combined device is provided with a number of microwave generators on the microwave drying furnace and the microwave pyrolysis furnace respectively and is used for waste salt heating to provide energy.

[0014] Further, a waste salt drying and pyrolysis double-layer combined device adopts water cooling for a cooling system and is used for cooling the cavity and the cathode part of the microwave tube.

[0015] Further, a waste salt drying and pyrolysis double-layer combined device includes a PLC and an upper computer and various online measuring instruments such as a thermometer (thermocouple).

[0016] The beneficial effects of the present application are: 1) The present invention's dual-layer combined device for waste salt drying and pyrolysis combines the drying and pyrolysis processes. The microwave drying and pyrolysis equipment are arranged in two layers, one above the other, saving space and achieving high space utilization. The combined device allows for unified microwave source control, and the microwave drying furnace's discharge port is interconnected with the microwave pyrolysis furnace's feed port, eliminating intermediate storage and secondary transport of materials, reducing transport energy consumption and heat loss, and conserving energy.

[0017] 2) The present invention's dual-stage combined waste salt drying and pyrolysis device, through internal piping, relies on the input of protective gas and the output of an exhaust blower to direct the high-temperature exhaust gas generated by the microwave pyrolysis furnace into the microwave drying furnace. While microwaves are drying the raw waste salt, the high-temperature exhaust gas is also used to simultaneously dry the raw waste salt. This not only recycles the heat from the high-temperature exhaust gas but also reduces the microwave energy required in the microwave drying stage. Through the combined effects of thermal radiation and convection, energy savings and consumption reductions are achieved in the drying process.

[0018] 3) In the double-layer combined device for drying and pyrolysis of waste salt of the present invention, the temperature of the microwave drying section is controlled at 90-150°C, reducing the moisture content of the discharged material to less than 3%. The temperature of the microwave pyrolysis section is controlled at 400-650°C, reducing the TOC of the discharged waste salt to less than 100 mg / kg. Under a slightly negative pressure state (-5Pa to -10Pa), the interior of the microwave kiln is an oxygen-free process, the exhaust gas volume is small, and no harmful substances such as dioxins are generated. The exhaust gas can be sent to the RTO furnace for incineration. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a double-layer combined device for drying and pyrolysis of waste salt; In the figure: 1. Raw material waste salt warehouse; 2. Feed hopper elevator; 3. Microwave drying furnace; 4. Microwave pyrolysis furnace; 5. Discharge screw conveyor; 6. Pyrolysis waste salt warehouse; 7. Cooling system; 8. Exhaust fan; 9. Control system. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the following examples. The following examples are provided only to facilitate understanding of the present invention. It should be noted that, without departing from the principles of the present invention, it is possible for a person skilled in the art to make various modifications to the present invention, and such improvements and modifications fall within the scope of the claims of the present invention. Example

[0021] like Figure 1 As shown, a double-layer combined device for drying and pyrolysis of waste salt includes: a raw material waste salt warehouse 1, a feed hopper elevator 2, a microwave drying furnace 3, a microwave pyrolysis furnace 4, a discharge screw conveyor 5, a pyrolysis waste salt warehouse 6, a cooling system 7, an exhaust fan 8 and a control system 9.

[0022] The discharge port of the raw material waste salt bin 1 is connected to the feed inlet of the feed hopper elevator 2, the microwave drying furnace 3 is located on the second floor, the discharge port of the feed hopper elevator 2 is connected to the feed inlet of the microwave drying furnace 3, the microwave pyrolysis furnace 4 is located on the first floor, the feed inlet of the microwave pyrolysis furnace 4 is connected to the discharge port of the microwave drying furnace 3, and the discharge port of the microwave pyrolysis furnace 4 is provided with a discharge screw conveyor 5 and is connected to the pyrolysis waste salt bin 6 through the discharge screw conveyor 5.

[0023] Specifically, the feed inlet of the microwave drying furnace 3 is located on one side and opens upward, the discharge port of the microwave drying furnace 3 is located on the other side and opens downward, the feed inlet of the microwave pyrolysis furnace 4 is located on one side and opens upward, and is opposite to the discharge port of the microwave drying furnace 3 and is connected and sealed through a vertical pipeline, and the discharge port of the microwave pyrolysis furnace 4 is located on the other side and opens downward.

[0024] The waste salt is sequentially sealed and transported through the raw material waste salt bin, the feed hopper elevator, the microwave drying furnace, the microwave pyrolysis furnace, the vertical pipeline, the discharge screw conveyor and the pyrolysis waste salt bin, and the raw material waste salt bin, the feed hopper elevator, the microwave drying furnace, the microwave pyrolysis furnace, the vertical pipeline, the discharge screw conveyor and the pyrolysis waste salt bin are all provided with an insulation layer outside.

[0025] The discharge port of the microwave pyrolysis furnace 4 is provided with a nitrogen protection gas inlet, and a nitrogen protection system is connected to the nitrogen protection gas inlet for internal atmosphere protection.

[0026] The feed inlet of the microwave drying furnace 3 is provided with a tail gas discharge port, and a tail gas fan 8 is connected to the tail gas discharge port for internal atmosphere protection and tail gas extraction, so as to ensure that the microwave kiln is operated in a state of micro negative pressure (-5 Pa to -10 Pa).

[0027] The cooling system 7 adopts water cooling for cooling the cavity and cathode part of the microwave tube, a circulating water path is arranged on the microwave generator shell, the circulating water path has water inlets and outlets, a water pump is used for circulation, and the microwave generator equipment matched with the microwave drying furnace 3 and the microwave pyrolysis furnace 4 is cooled and protected.

[0028] The control system 9 includes a PLC, an upper computer and a thermocouple, the microwave drying furnace and the microwave pyrolysis furnace are respectively provided with thermocouples for collecting material temperature data, and the output power of the microwave generator is adjusted in real time through the control system for temperature control operation. Embodiment

[0029] The raw material waste salt is stored in the raw material waste salt bin 1, falls into the feeding hopper elevator 2 through the bottom discharge port, and is conveyed to the second floor by the feeding hopper elevator; the discharge port of the feeding hopper elevator 2 is connected to the feeding port of the microwave drying furnace 3, and the waste salt is conveyed forward by the plate chain conveyor in the microwave drying furnace 3; in the conveying process, the waste salt is dried by microwave heating and high-temperature tail gas; the high-temperature tail gas and the water vapor carried out by drying are extracted from the system by the tail gas fan 8; the discharge port of the microwave drying furnace 3 is located on the other side of the feeding port and opens downward, and is connected to the feeding port of the microwave pyrolysis furnace 4 on the first floor through a vertical pipeline; the waste salt is conveyed forward by the spiral conveyor in the microwave pyrolysis furnace 4, and in the conveying process, the TOC in the waste salt is decomposed at high temperature by microwave heating; the protective gas is connected near the discharge port of the microwave pyrolysis furnace 4, and works together with the tail gas fan 8 to make the inside of the device in a micro-negative pressure state, and no oxygen process produces hydrogen, carbon dioxide and a small amount of impurity gas and water vapor; the discharge port of the microwave pyrolysis furnace 4 is connected to the feeding port of the discharge spiral conveyor 5, and the discharge port of the discharge spiral conveyor 5 is connected to the feeding port of the pyrolysis waste salt bin 6, and the pyrolyzed waste salt enters the subsequent processing facilities; the control system 9 adjusts the microwave generator power in real time by monitoring the temperature measuring points arranged in the microwave drying furnace 3 and the microwave pyrolysis furnace 4, so as to ensure the microwave drying and pyrolysis efficiency and reduce the operation energy consumption of the overall system.

[0030] The above embodiments are only preferred embodiments of the present application, and are not a limitation on the technical solutions of the present application. Any technical solutions that can be realized on the basis of the above embodiments without creative labor shall be considered to fall within the protection scope of the present application.

Claims

1. A double-layer combined device for drying and pyrolyzing waste salt, comprising a waste salt feeding system, a microwave drying furnace, a microwave pyrolysis furnace, and a pyrolysis waste salt bin; the waste salt feeding system comprises a raw waste salt bin and a feeding hopper elevator, the discharge port of the raw waste salt bin is connected to the feeding port of the feeding hopper elevator, the microwave drying furnace is located on a second floor, the discharge port of the feeding hopper elevator is connected to the feeding port of the microwave drying furnace, the microwave pyrolysis furnace is located on a first floor, the feeding port of the microwave pyrolysis furnace is connected to the discharge port of the microwave drying furnace, a discharge screw conveyor is arranged at the discharge port of the microwave pyrolysis furnace, and the discharge screw conveyor is connected to the pyrolysis waste salt bin.

2. A double layered combined apparatus for drying and pyrolysis of waste salt as claimed in claim 1 wherein, The device further comprises a tail gas fan, a tail gas discharge port is arranged near the feeding port of the microwave drying furnace, and the tail gas fan is connected to the tail gas discharge port, which is used for internal atmosphere protection and tail gas extraction to ensure the internal micro-negative pressure state of the microwave furnace.

3. A double layered combined apparatus for drying and pyrolysis of waste salt as claimed in claim 1 wherein, The device further comprises a nitrogen protection system, a nitrogen protection gas path inlet is arranged near the discharge port of the microwave pyrolysis furnace, and the nitrogen protection system is connected to the nitrogen protection gas path inlet, which is used for internal atmosphere protection.

4. The double layered combined device for drying and pyrolysis of waste salt as claimed in claim 1 wherein, The feeding port of the microwave drying furnace is located on one side and opens upward, the discharge port of the microwave drying furnace is located on the other side and opens downward, the feeding port of the microwave pyrolysis furnace is located on one side and opens upward, and is opposite to the discharge port of the microwave drying furnace and is connected to the discharge port of the microwave drying furnace through a vertical pipeline; the discharge port of the microwave pyrolysis furnace is located on the other side and opens downward.

5. A double layered combined apparatus for drying and pyrolysis of waste salt as claimed in claim 1 wherein, A plurality of microwave generators are arranged on the microwave drying furnace and the microwave pyrolysis furnace respectively, which are used for heating the waste salt and providing energy.

6. A double layered combined apparatus for drying and pyrolysis of waste salt as claimed in claim 1 wherein, The control system comprises a PLC, an upper computer, and thermocouples, the microwave drying furnace and the microwave pyrolysis furnace are respectively provided with thermocouples for collecting material temperature data, and the output power of the microwave generators is adjusted in real time by the control system for temperature control.

7. A double layered combined apparatus for drying and pyrolysis of waste salt as claimed in claim 4 wherein, The waste salt is sequentially and sealingly conveyed through the raw waste salt bin, the feeding hopper elevator, the microwave drying furnace, the microwave pyrolysis furnace, the vertical pipeline, the discharge screw conveyor, and the pyrolysis waste salt bin, and the raw waste salt bin, the feeding hopper elevator, the microwave drying furnace, the microwave pyrolysis furnace, the vertical pipeline, the discharge screw conveyor, and the pyrolysis waste salt bin are all externally provided with an insulation layer.

8. The working process of a double-layer combined device for drying and pyrolyzing waste salt according to any one of claims 1-7, characterized in that, The device comprises the following steps: The raw waste salt is stored in the raw waste salt bin, falls into the feeding port of the feeding hopper elevator through the bottom discharge port, and is conveyed and climbed to the second floor by the feeding hopper elevator; the discharge port of the feeding hopper elevator is connected to the feeding port of the microwave drying furnace, and the waste salt is conveyed forward by the plate chain conveyor in the microwave drying furnace; During the conveying process, the waste salt is dried by microwave heating and high-temperature tail gas; the high-temperature tail gas and the water vapor carried out during the drying process are extracted from the system by the tail gas fan; The discharge port of the microwave drying furnace is located on the other side of the feeding port and opens downward, and is connected to the feeding port of the microwave pyrolysis furnace on the first floor through a vertical pipeline; the waste salt is conveyed forward by the screw conveyor in the microwave pyrolysis furnace, and the TOC in the waste salt is decomposed at high temperature by microwave heating during the conveying process; nitrogen protection gas is connected to the discharge port of the microwave pyrolysis furnace, and the device is in a micro-negative pressure state under the joint action of the tail gas fan. The discharge port of the microwave pyrolysis furnace is connected with the feeding port of the discharge screw conveyor, and the discharge port of the discharge screw conveyor is connected with the feeding port of the pyrolyzed waste salt bin, so that the waste salt after pyrolysis enters the subsequent processing facility; The control system adjusts the microwave generator power in real time by monitoring the temperature measuring points arranged in the microwave drying furnace and the microwave pyrolysis furnace, so as to reduce the operation energy consumption of the whole system while guaranteeing the microwave drying and pyrolysis efficiency.

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