Equipment for combusting waste sand by using electric fire

Abstract

An apparatus (1) for the burning of waste sand by an electric stove (3a) that does not require combustion improvers comprises an electric burning device (3) and a first separator (6) as well as a flow diverter (7). The electric fire pyrolyzer (3) guides electric fire flames (3b) of the electric fire stove (3a) through the first airflow (2) to pyrolyze the waste sand (4) so that waste sand sticking substances can be decomposed. The first separator (6) separates waste sand from the first gas stream (2). A flow diverter (7) directs the first gas stream (2) from the first separator (6) to the electric fire pyrolyzer (3).

Description

Invention Field

[0001] This invention relates to an environmentally friendly and energy-saving device, namely a device for burning waste sand by electric arc. Technical Background

[0002] For a long time, recycling equipment for burning fossil fuels has been used to reduce the mining of silica sand and some mineral sands used for molding. However, burning fossil fuels and biofuels to decompose waste sand produces carbon dioxide and other pollutants. The use of combustion aids, such as air-assisted hydrogen combustion, can cause nitrogen and oxygen in the air to generate pollutants, such as nitrogen oxides (NOx). Even if the waste gas produced by combustion is treated with adsorbents, new pollutants can easily be generated, such as waste adsorbents.

[0003] In short, the traditional method of treating waste sand by burning fuel and oxidizers, followed by releasing the combustion fumes into the atmosphere, causes environmental pollution.

[0004] Therefore, there is a need for a technology that would facilitate the recycling of waste sand without the limitations of traditional technologies. Invention Objective

[0005] The objective of this invention is to provide a technique for decomposing waste sand aggregates by burning waste sand with an electric flame. Invention Overview

[0006] According to the present invention, an apparatus for electro-fired combustion of waste sand heated by an electric stove includes an electro-fired burner, a first separator, and a diverter.

[0007] The electric flame burner is configured to burn the adhesive material of waste sand using a first airflow from an electric stove. More specifically, the first airflow guides the electric flame of the electric stove to burn the waste sand, causing the surface adhesive material of the waste sand to decompose, for example, into resin. Advantageously, the first airflow guides the waste sand to form a vortex flow. The inner wall of the burning chamber used for burning the waste sand is an arc-shaped inner wall, and the concave surface of the arc-shaped inner wall is opposite to the direction of the nozzle used to inject the first airflow. This causes the waste sand to undergo centrifugal motion along the arc-shaped inner wall under the action of the first airflow, thereby slowing down the falling speed of the waste sand in the free fall direction and prolonging the burning time. Preferably, the arc length of the arc-shaped inner wall is greater than 50% of the distance from the beginning to the end of the arc-shaped inner wall.

[0008] The first separator of the preferred cyclone separator is configured to separate the sintered waste sand from the first gas flow.

[0009] Preferably, the flow guide, which includes a fan, is configured to circulate and guide the first gas flow from the first separator to the electric flame burner. Advantageously, the oxygen content in the first gas flow will be even lower after it has been burned and then heated by the electric flame. The less oxygen in the first gas flow, the more conducive it is to the decomposition of the waste sand aggregate.

[0010] Optionally, the device may include a preheater configured to heat the waste sand with a first gas flow separated by a first separator. If so, the preheater heats the waste sand that will enter the sintering chamber with the first gas flow guided from the first separator. The preheater includes a second separator, preferably of the cyclone separator type, and the first gas flow is separated from the waste sand by the preheater. After separation, the first gas flow is guided from the preheater to the diverter by a diverter.

[0011] Optionally, the device may include a deaerator configured to heat waste sand and remove oxygen. If so, the deaerator may include a heat exchanger that indirectly heats new waste sand by discharging calcined waste sand from a first separator and a third separator that separates the waste sand from oxygen and water vapor. The heat exchanger has an outlet that guides the heated waste sand from the heat exchanger to the outlet of the third separator, and the third separator has an outlet that guides oxygen and water vapor and an outlet that discharges deoxygenated waste sand.

[0012] According to other aspects of the invention, the deaerator includes an inlet for guiding deoxygenated waste sand to an electro-fired pyrolysis unit. The deaerator further includes a configuration for recirculating a second airflow from a third separator to guide the deoxygenated waste sand from the third separator to a fourth separator, and a second fan guides the second airflow separated from the fourth separator to a discharge port of the third separator, and the discharge port of the fourth separator is in communication with the electro-fired pyrolysis unit. If the device includes a preheater, the fourth separator may be in communication with the preheater.

[0013] The beneficial effects of this invention are as follows: This invention facilitates the use of an electric stove that does not require combustion aids to burn waste sand, decomposing the aggregates in the waste sand and thereby reducing exhaust emissions. Simultaneously, the first airflow circulation guiding the electric flame to heat the waste sand helps reduce the oxygen content in the first airflow and improves thermal efficiency. If the waste sand is directly preheated using the circulating first airflow, it facilitates rapid temperature rise. Furthermore, if an aerator is used to remove oxygen from the waste sand, less oxygen is present during the burning process, resulting in higher burning efficiency. Additionally, the use of a second airflow circulation to transport the deoxygenated waste sand reduces heat loss during transport. Brief description of the attached diagram Figure 1 An apparatus for electro-fired waste sand according to the present invention is described, which includes a device for guiding a first airflow of electric flame from an electric stove to decompose the waste sand aggregate. Figure 2 The structure of the sintering chamber of the electric sintering device is described.

[0014] The diagram shows: 1. Electro-fired waste sand incineration stage; 2. First airflow; 2a. First airflow in the first part; 2a′. First airflow in the second part; 2a″. First airflow in the third part; 2b. First flame; 2b′. First airflow in the second flame; 2b″. First airflow in the third flame; 2d. First flame sand; 2c. First flame sand; 2c′. First flame sand; 2c″. First airflow in the third flame sand; 3. Electro-fired incinerator; 3a. Electric stove; 3b. Electric flame; 3b′. Nozzle; 3c. Second... Nozzle 3c′; Third nozzle 3c″; Waste sand 4; Deoxygenated waste sand 4a; Calcination waste sand 4b; Calcination chamber 5; First separator 6; Drainage device 7; First fan 8; Preheater 9; Second separator 10; Deaerator 11; Heat exchanger 12; Third separator 13; Oxygen 14; Water gas 14a; Feeder 15; Second airflow 16; Fourth separator 17; Second fan 18; Vortex flow 19; Second vortex flow 19′; Inner wall 20; Circular arc inner wall 20a; First circular arc inner wall 20a; Second circular arc inner wall 20a′. Detailed Implementation The general concept of this invention is to decompose the binders, such as resins, in waste sand by thermal decomposition, in particular by burning the waste sand with an electric flame from an electric stove that does not require an accelerant, and by guiding the electric flame with a circulating airflow to reduce the oxygen content in the first airflow, thereby enabling the waste sand binders to decompose more thoroughly in a high-temperature environment.

[0015] The first implementation example Figure 1 As shown: The first airflow 2 is received through the inlet of the electric stove. The first airflow flows through the electrically generated flame and guides the electric flame 3b to be sprayed in the electric burner 3. The waste sand 4 is burned with the flame airflow that does not contain combustion aid, so that the waste sand binder is thermally decomposed. As those skilled in the art will understand, the waste sand binder, such as resin, can be decomposed under high temperature (e.g., above 700°C) and oxygen-deficient conditions.

[0016] Therefore, in order to fully decompose the waste sand aggregate, the electro-fire burner establishes an environment in which the first airflow circulation used to guide the electro-fire flame 3b is reduced to allow for more complete decomposition of the waste sand aggregate.

[0017] like Figure 1 As shown: During the process, conditions are established in the electric flame burner 3 such that the first airflow 2 guides the electric flame 3b of the electric stove 3a to instantly reach a high temperature, for example, >1000°C, and the temperature of the waste sand is burned to a temperature that can cause the waste sand 4 binder, such as resin, to reach a decomposition temperature, for example, above 700°C. Then, the first airflow 2d that has burned the waste sand is discharged from the electric flame burner 3 to the first separator 6 through the outlet of the electric flame burner 3.

[0018] The first separator 6 is preferably a mechanical separator, such as a cyclone separator. Figure 1 As shown, but this is not mandatory, and another type of separator can be used, the first separator functions to receive the first gas flow 2c of calcination including decomposed binder waste sand through the inlet and to separate the first gas flow 2 in the first gas flow 2d of calcination including calcined calcined waste sand 4b from the calcined waste sand 4b.

[0019] To reduce the oxygen content in the first gas flow, the first gas flow 2 will be separated by the first separator 6 and guided from the first separator 6 to the inlet of the first gas flow 2b of the electric arc burner 3, as shown below. Figure 1 As shown, a guide 7 is provided between the outlet of the first gas flow 2 of the first separator 6 and the inlet of the first gas flow 2 of the electro-fired burner 3 to guide the first gas flow 2 from the first separator 6 to the electro-fired burner 3. The guide 7 includes a preferred first fan 8. The outlet of the first gas flow 2 of the guide 7 is connected to the inlet of the first gas flow 2 of the electro-fired burner 3, which allows the first gas flow to be recirculated. The recirculation of the first gas flow reduces the oxygen in the first gas flow. Therefore, the recirculated first gas flow 2 passes through the electric flame 3b of the electro-fired burner and then burns the waste sand 4, so that the adhering material of the waste sand 4, such as resin, is fully decomposed.

[0020] During the sintering process, conditions are created in the sintering chamber such that the first airflow, including the electric flame, and the first airflow of the waste sand merge into a vortex flow, which slows down the falling speed of the waste sand in the free fall direction and increases the sintering time.

[0021] like Figure 2 As shown, in order to fully calculate the waste sand, the inner wall 20 of the calcination chamber 5 is configured as an arc-shaped inner wall 20a. The arc-shaped inner wall can have a stroke such that the arc length of the inner wall is greater than 50% of the distance from the start point to the end point of the arc. Correspondingly, the electric stove 3a is configured as a nozzle 3c opposite to the arc-shaped inner wall 20a. The first flame and first airflow 2b are sprayed from the nozzle 3c onto the arc-shaped inner wall 20a. The waste sand 4 is mixed into the first flame and first airflow 2c under the action of the first flame and first airflow 2b, and undergoes centrifugal motion along the arc-shaped inner wall 20a to form a vortex flow 19. This can extend the stroke of the waste sand by more than 50% compared to the free fall stroke from the start point to the end point of the arc. Even more advantageously, the centrifugal motion of the waste sand along the inner arc wall can change the velocity and flow direction of the waste sand particles along the center direction of the first airflow nozzle compared to the particles around the center. For example, the waste sand may change its direction of motion due to collision or friction with the inner arc wall. Additionally, when the first airflow of waste sand contacts the arc-shaped inner wall of the sinterer, it will facilitate the formation of a waste sand film flowing along the arc. This film, moving from the flow beam of the first airflow to the waste sand film spreading along the inner arc wall, may also be affected by the heat radiation from the inner wall, resulting in more uniform heating of the waste sand particles and higher sintering efficiency. After leaving the inner arc wall, the waste sand will flow along the direction of gravity. Figure 2As shown, this example illustrates two circular inner walls, but this is not mandatory and there can be multiple circular inner walls 20a.

[0022] The nozzle 3c corresponds to the inner wall 20a of the first circular arc. The first airflow 2a guides the electric flame 3b to spray the first flame first airflow 2b from the nozzle 3c. The first flame first airflow 2b then guides the waste sand falling from the inlet. The waste sand can be various mineral sands and mineral sand 4 including binders. Here, it is exemplified as deoxygenated waste sand 4b after removing oxygen. The first flame sand first airflow 2c including the deoxygenated waste sand 4b enters the inner wall 20a of the first circular arc along the tangential direction and makes centrifugal motion along the inner wall 20a of the first circular arc, thereby forming a vortex flow 19 of the first flame sand first airflow 2c. During this period, the deoxygenated waste sand 4b with a larger mass (relative to the airflow) in the first flame sand and first airflow 2c will be closer to the inner arc wall 20a, which is conducive to the formation of a thin film flow along the inner arc wall. This will facilitate more uniform heating of the waste sand. The friction and impact that may occur between the waste sand and the high-temperature inner arc wall 20a under inertia will also help to rapidly heat up the waste sand and improve the decomposition efficiency of the waste sand aggregate. After the first flame sand and first airflow containing the waste sand leaves the first inner arc wall 20a, the deoxygenated waste sand 4b will flow downwards in the free fall direction. Figure 2 As shown, the second nozzle 3c′ corresponds to the second arc inner wall 20a′. The second part of the first airflow 2a′, which is split from the first airflow 2, guides the second electric flame 3b′ of the second nozzle 3c′. The second electric flame first airflow 2b′, including the second electric flame, then guides the deoxygenated waste sand 4b falling from the first arc inner wall 20a. The second flame sand first airflow 2c′, including the deoxygenated waste sand 4b, will form a second vortex flow 19′ along the second arc inner wall 20a′. Passing through the second arc inner wall 20a will make the waste sand more evenly heated and the decomposition of the waste sand aggregate more complete. The deoxygenated waste sand 4b leaving the first arc inner wall 20a will fall along the inner wall 20. The second flame first airflow 2b′ ejected by the second nozzle 2c′ will generate a negative pressure zone on the side near the second nozzle 3c′. This will facilitate the flow of the first flame first airflow 2c from the first arc inner wall 20a through the periphery of the second nozzle 3c′.

[0023] like Figure 2 As shown, the sintering chamber 5 is equipped with a third nozzle 3c″. The third part of the first airflow 2b″, which includes the third electric flame and is separated from the first airflow 2, is injected from the third nozzle to further sinter the deoxygenated waste sand 4a. The sintering first airflow 2d, which includes the first flame first airflow 2b flowing through the periphery of the second nozzle and the second flame first airflow 2b′ flowing through the inner wall of the second circular arc and the freely falling deoxygenated waste sand 4b, is discharged from the outlet of the sintering chamber 5 to the first separator 6.

[0024] To enable rapid combustion of waste sand in the electro-fired calciner 3, the waste sand can be preheated before entering the electro-fired calciner 3. To achieve this, in the described implementation, a preheater 9 is provided at the inlet of the electro-fired calciner 3, and the waste sand is heated by a first airflow 2 guided from the first separator 6. The preheater 9 includes a preferred mechanical separator type, such as a cyclone separator. Figure 1 As shown, but this is not mandatory, and another type of separator can be used. The preheater 9 functions to provide a waste sand inlet between the first separator 6 and the preheater 9, and the waste sand is conveyed into the preheater 9 by a first airflow guided from the first separator 6 to the preheater 9. As... Figure 1 As shown, a waste sand inlet is provided between the outlet of the first airflow 2 of the first separator and the inlet of the first airflow 2 of the preheater 9. The waste sand discharge port of the preheater 9 is connected to the inlet of the electric burner 3, and the outlet of the first airflow 2 of the preheater 9 is connected to the guide 7.

[0025] In this way, the first airflow 2, which is at a high temperature, for example 800°C, guided from the first separator, directly exchanges heat with the new waste sand 4. The heat exchange can give the waste sand 4 a higher temperature, for example 500°C. The higher temperature of the waste sand 4 will help it to be heated to the decomposition temperature quickly when it enters the electric fire burner.

[0026] Optionally, the deaerator 11 is connected to the discharge port of the first separator 6 waste sand 4b. The deaerator 11 functions to indirectly heat new waste sand 4 from the calcined waste sand 4a discharged from the first separator, causing the free water in the waste sand 4 to be converted into water vapor. The water vapor carries the oxygen (if any) contained in the waste sand, and then the water vapor and oxygen are separated from the waste sand, thereby removing the oxygen from the waste sand. Removing oxygen from the waste sand will facilitate the rapid decomposition of the waste sand aggregates. If this is the case, then in... Figure 1 The deaerator 11 depicted may be included in an electro-fired waste sand calcination device, such as... Figure 1 The deaerator 11 shown includes a heat exchanger 12 and a third separator 13. New waste sand 4 is received through the inlet of the heat exchanger and heated by waste sand 4b with a higher temperature discharged from the first separator 6. The new waste sand 4 is then guided through the outlet of the heat exchanger 12 to the inlet of the waste sand 4 of the third separator 13. The third separator separates water vapor 14a containing oxygen 14 from the waste sand 4 and discharges deaerated waste sand 4a from the outlet.

[0027] If pneumatic conveying of waste sand is desired, a feeder 15 can be configured with a second airflow 16 guided by a second blower 18, and the second blower 18 guides deoxygenated waste sand 4a from the third separator 13 to the fourth separator. The fourth separator 17 is connected to the inlet of waste sand 4 or deoxygenated waste sand 4a between the first separator 6 and the diverter 7. If a preheater 9 is included, the discharge port of the fourth separator 17 connects the waste sand 4 or deoxygenated waste sand 4a to the inlet between the first separator 6 and the preheater 9.

Claims

1. A device for electro-fired combustion of waste sand includes: An electric burner is configured to use a first airflow to guide the electric flame of an electric stove to burn waste sand and decompose the waste sand aggregates. The electric burner is equipped with a burner chamber. A first separator configured to separate the calcined waste sand from the first gas flow; A flow guide, configured to circulate the first gas flow from the first separator to the electric arc burner, is provided, the flow guide including a first fan.

2. The equipment for electro-fired combustion of waste sand according to claim 1, characterized in that it further comprises: A preheater, the preheater being configured to preheat the waste sand with a second separator by guiding the first airflow from the first separator, the second separator including an inlet for guiding the first airflow from the first separator to the second separator, and including an outlet for guiding the first airflow from the second separator to the inlet of the diverter, and the inlet of the waste sand being between the first separator and the diverter.

3. The equipment for electro-fired combustion of waste sand according to claim 1, characterized in that it further comprises: A deaerator configured to heat new waste sand with a heat exchanger from the calcined waste sand discharged from the first separator and a third separation stream for separating oxygen, the third separation stream including a discharge port for discharging the waste sand.

4. The equipment for electro-fired combustion of waste sand according to claim 3, characterized in that it further comprises: A feeder is configured to guide the waste sand from the discharge port of the third separator to the fourth separator using a second airflow and to separate the waste sand from the second airflow; the feeder includes a second fan for guiding the second airflow from the fourth separator back to the discharge port.

5. The equipment for electro-fired calcination of waste sand according to claim 1, characterized in that: Further includes: The sintering chamber includes one or more arcuate inner walls configured to cause the first airflow to form a vortex flow, and to cause the waste sand to move centrifugally along the arcuate inner walls.

6. The device for electro-fired combustion of waste sand according to claim 5, characterized in that: the arc length of the inner wall of the arc is greater than 50% of the distance from the start point to the end point of the arc, so that the travel distance of the waste sand along the inner wall of the arc is greater than 50% of the travel distance along the free fall.

7. A method for electrolytic combustion of waste sand, comprising: The waste sand is decomposed by using a first airflow to guide an electric flame to burn the waste sand and break down the waste sand aggregate. This separates the waste sand, which has been decomposed and adhered to the first airflow, from the waste sand. The first airflow, after being separated from the waste sand, is then used to guide the electric flame.

8. The method according to claim 7, further comprising: The waste sand is preheated with the first airflow, and then the waste sand is separated from the first airflow.

9. The method according to claim 7, characterized in that: Further includes: The waste sand, after being decomposed and bound, is heated to separate the waste sand from its oxygen.

10. The method according to claim 9, characterized in that: Further includes: The waste sand from which oxygen has been separated is transported by a second airflow, thereby separating the waste sand from the second airflow, and then transporting the waste sand from which oxygen has been separated again by the second airflow after separation.

11. The method according to claim 7, characterized in that: Further includes: The first airflow is made into a vortex flow, and the distance traveled by the waste sand is greater than 50% of the free fall distance.

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