CN109654882B - Method for recycling waste foundry sand based on compound roasting equipment - Google Patents
Method for recycling waste foundry sand based on compound roasting equipment Download PDFInfo
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- CN109654882B CN109654882B CN201811381354.XA CN201811381354A CN109654882B CN 109654882 B CN109654882 B CN 109654882B CN 201811381354 A CN201811381354 A CN 201811381354A CN 109654882 B CN109654882 B CN 109654882B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
- F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
- F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
- F27B15/08—Arrangements of devices for charging
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
- F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
- F27B15/10—Arrangements of air or gas supply devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
- F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
- F27B15/14—Arrangements of heating devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
- F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
- F27B15/16—Arrangements of cooling devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
Abstract
The invention discloses a method for recycling waste foundry sand based on duplex roasting equipment, which comprises the following steps: s1, feeding materials into a receiving tank through a material homogenizing plate, feeding the materials into a feeding protection device through an impeller, and feeding the materials into a horizontal combustion chamber; s2, blowing and boiling the material by hot air at the bottom of the combustion chamber, flowing from one end of the combustion chamber to the opposite end of the combustion chamber, and sequentially carrying out three-stage roasting in the period, wherein the temperature of the first-stage roasting is 300-400 ℃ and the time is 10-20 s; the temperature of the secondary roasting is 600-800 ℃, and the time is 180-240 s; the temperature of the three-stage roasting is 850-900 ℃, and the time is 10-20 s; s3, feeding the roasted material into an air preheating chamber, performing heat exchange between the material and cold air, cooling to 200-300 ℃, discharging, and discharging high-temperature waste gas after heat exchange. The recycling method has the advantages that the discharging temperature is lower than 300 ℃, the temperature rising speed of the furnace temperature is high, the roasting temperature of the materials is lower than 30 minutes, the temperature of the discharged waste gas is low, and the harmful substances are few.
Description
Technical Field
The invention belongs to the technical field of material roasting, and particularly relates to a method for recycling waste foundry sand based on compound roasting equipment.
Background
Approximately 90% of castings in the foundry industry are produced by sand casting. The basic raw materials for manufacturing the sand mold are foundry sand and a molding sand binder, the common molding sand binder can be divided into an organic type (such as phenolic resin, cold box resin and the like) and an inorganic type (such as clay, water glass and the like), while the common foundry sand is silica sand (20-140 meshes of particles), 1 ton of foundry waste sand is generated when 1 ton of castings are produced, a large amount of silica sand comes from the nature, and the scale development of the foundry industry necessarily causes the large exploitation of natural silica sand resources and the discarding of a large amount of waste sand containing harmful substances. In order to realize sustainable development of the foundry industry, the foundry waste sand needs to be recycled so as to protect the earth resources and the environment.
One method for thermal regeneration of waste foundry sand disclosed at present is to heat the waste sand to 800 ℃ in a vertical roasting furnace to burn the waste sand, so as to burn out the impurities on the surface of the silica sand, thereby achieving the purpose of stripping regeneration. The existing thermal regeneration method has the disadvantages of insufficient combustion of waste foundry sand and waste gas, large waste gas discharge, poor environmental protection effect and relatively high heat loss. The main reason is that the feeding mode of the vertical roasting furnace is from top to bottom, the combustion chamber is arranged at the bottom, the casting waste sand is heated in the feeding process and can not reach the combustion temperature, organic matters stuck on the casting waste sand are volatilized and discharged, the waste gas is directly discharged without heat exchange, the heat loss is large, the sand discharging temperature is high, and the energy consumption is high. For example, CN201620006956.7 discloses a horizontal used sand roasting furnace, and CN201710427201.3 discloses another vertical roasting furnace, which are two types of roasting furnaces commonly used in the prior art, and both of which have the disadvantages.
Disclosure of Invention
The invention aims to design a method for recycling waste foundry sand based on compound roasting equipment, aiming at solving the problems in the prior art, and the method has the advantages of lower energy consumption, higher combustion efficiency, more energy conservation and more environmental protection.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a method for recycling waste foundry sand based on duplex roasting equipment,
the compound roasting equipment is provided with a horizontal combustion chamber, the horizontal combustion chamber is divided into a combustion chamber and a wind selection impurity removal chamber, and the combustion chamber and the wind selection impurity removal chamber are mutually and transversely communicated;
a feeding mechanism is arranged at one end of the combustion chamber, which is far away from the air separation impurity removal chamber, and the feeding mechanism is used for conveying materials into the combustion chamber; a plurality of combustion guns are arranged on the side surface of the combustion chamber, and the combustion guns jet combustion flame towards the inside of the combustion chamber; a plurality of air caps are arranged at the bottom of the combustion chamber, the lower ends of the air caps are communicated with a hot air bellow, the hot air bellow comprises a first air inlet, and hot air enters the hot air bellow from the first air inlet and then is blown into the combustion chamber through the air caps;
a heat exchange chamber is communicated above the air separation impurity removal chamber, a first air outlet is formed in the upper end of the heat exchange chamber, and high-temperature waste gas generated after roasting enters the heat exchange chamber and is discharged from the first air outlet; a heat exchanger is arranged in the heat exchange chamber, and a plurality of heat exchange tubes are arranged on the heat exchanger; the heat exchanger comprises a second air inlet and a second air outlet, cold air enters the heat exchanger from the second air inlet, and is changed into hot air after exchanging heat with high-temperature waste gas and then is discharged from the second air outlet; the second air outlet is connected with the first air inlet, and hot air of the second air outlet enters the hot air bellows from the first air inlet;
the lower part of the air separation impurity removal chamber is communicated with an air preheating chamber, the lower end of the air preheating chamber is provided with a discharge pipe, and roasted high-temperature materials fall into the air preheating chamber, are discharged through the discharge pipe at the lower end of the air preheating chamber, fall into a material receiving hopper and are discharged from a discharge port; a plurality of spiral heat exchange tubes are arranged in the air preheating chamber, the upper ends of the spiral heat exchange tubes are provided with air nozzles, the lower ends of the spiral heat exchange tubes are communicated with a cold air bellow, the cold air bellow comprises a third air inlet, cold air sequentially enters the cold air bellow and the spiral heat exchange tubes from the third air inlet, and after heat exchange with roasted high-temperature materials through the spiral heat exchange tubes in the air preheating chamber, the cold air is blown into a winnowing impurity removal chamber from the air nozzles;
the method for recycling the waste foundry sand based on the duplex roasting equipment comprises the following steps:
s1, feeding materials into a receiving groove through a material homogenizing plate, feeding the materials into a feeding protection device through an impeller, and feeding the materials into a combustion chamber of a horizontal combustion chamber;
s2, blowing and boiling the material by hot air at the bottom of the combustion chamber, flowing from the combustion chamber to the air separation and impurity removal chamber, and sequentially carrying out three-stage roasting by a combustion gun in the period, wherein the temperature of the first-stage roasting is 300-400 ℃ and the time is 10-20 s; the temperature of the secondary roasting is 600-800 ℃, and the time is 180-240 s; the temperature of the three-stage roasting is 850-900 ℃, and the time is 10-20 s;
s3, after the material is roasted, the material falls into an air preheating chamber from an air separation impurity removal chamber, exchanges heat with cold air of a spiral heat exchange tube in the air preheating chamber and is cooled to 200-plus-300 ℃ and then discharged, hot air exchanged by the spiral heat exchange tube is blown into the air separation impurity removal chamber through an air nozzle, so that the roasted material is in a boiling state, and the friction between the material and the material is increased to achieve the effect of further removing the impurities; waste gas generated by roasting the sundries and cold air of a heat exchanger on the upper part of the air preheating chamber are discharged after heat exchange and cooling, and hot air exchanged by the heat exchanger enters a hot air bellows.
According to the invention, the material homogenizing plate is arranged above the feeder, and materials uniformly enter the feeder through the material homogenizing plate and then fall into the combustion chamber, so that the materials can be uniformly distributed, and the materials are prevented from being stacked together and being boiled. After entering the combustion chamber, the material has two motion states, which are caused by the different structure of the roasting equipment: horizontal section and vertical section. The horizontal section is mainly used for boiling materials in a combustion chamber through a high-pressure fan or compressed air, and then three-stage roasting is carried out on the boiled casting waste sand and waste gas, wherein the temperature of the first-stage roasting is 300-400 ℃, and the time is 10-20 s; the temperature of the secondary roasting is 600-800 ℃, and the time is 180-240 s; the temperature of the three-stage roasting is 850-900 ℃, and the time is 10-20 s. Through three-stage roasting, the casting waste sand and the waste gas are fully combusted, no harmful and organic gas is volatilized, and the stripping rate, the impurity removal effect and the stability of the casting waste sand are greatly improved. The vertical section mainly enters the air preheating chamber from top to bottom through materials, high-pressure air exchanges heat with the high-temperature materials through the spiral heat exchange tubes buried in the materials to obtain hot air, the temperature in the roasting equipment is guaranteed not to be reduced, and the materials are cooled on the one hand. The sufficient heat exchange ensures that the discharging temperature of the materials is 200-300 ℃, and the discharging temperature of the other casting waste sand thermal regeneration method is 500-600 ℃. The heat exchanger is communicated above the air preheating chamber, high-temperature waste gas rises due to negative pressure generated by an air outlet at the top of the heat exchanger, and exchanges heat with cold air blown in from the heat exchanger, the cold air is preheated, and waste heat of the waste gas is reduced through the heat exchanger. Through the heat exchange of the two times, the preheated hot air is supplied to the combustion chamber to boil the materials and preheat the materials; the heat preservation effect is good, the temperature rising speed is high when the furnace is started, the roasting temperature of the material is raised to be lower than 30 minutes, and the temperature rising of other foundry waste sand thermal methods needs 90-120 minutes. The invention greatly reduces the energy consumption of the roasting furnace, and is energy-saving and environment-friendly.
Preferably, the temperature of the primary roasting is 400 ℃ and the time is 15 s; the temperature of the secondary roasting is 700 ℃ and the time is 240 s; the temperature of the three-stage roasting is 850 ℃ and the time is 10 s.
Preferably, the heat exchanger is communicated above the air preheating chamber, high-temperature hot air rises due to negative pressure generated by an air outlet at the top of the heat exchanger, and exchanges heat with cold air blown in by the heat exchanger, so that the cold air is preheated; the preheated hot air is supplied to the combustion chamber for use.
Preferably, the combustion chamber and the air separation and impurity removal chamber are raised to the roasting temperature of the material for less than 30 minutes.
Preferably, an insulating layer is arranged outside the heat exchange chamber.
Preferably, the side walls of the combustion chamber and the air separation impurity removal chamber are sequentially provided with a high-temperature-resistant and wear-resistant material, an insulating layer and a shell from inside to outside.
Preferably, the top of the combustion chamber and the air separation impurity removal chamber is sequentially provided with a high-temperature-resistant and wear-resistant material, an insulating layer and a shell from inside to outside.
Preferably, a maintenance access hole is formed in the side face of one end, far away from the air separation impurity removing chamber, of the combustion chamber.
Preferably, a part of the discharge pipe, which is located in the receiving hopper, is provided with a pneumatic blowing system, and the pneumatic blowing system blows air from the inside of the discharge pipe towards the outlet direction of the discharge pipe.
Preferably, the impeller is driven by a driving motor, the lower part of the impeller is a feeding hole, and a feeding protection device is arranged between the feeding hole and the combustion chamber.
Compared with the prior art, the invention has the beneficial effects that:
1. through twice heat exchange, the heat exchange effect of the materials and the hot air is stronger, the heat loss is small, and the heat energy is fully utilized and the energy consumption is lower. The air blown out by the air nozzle arranged at the upper end of the spiral heat exchange tube also enables the sand to be in a boiling state, and the sand is rubbed with the sand to enhance the impurity removal effect.
2. The multistage roasting and the channel space limitation enable the materials and the waste gas to be more fully roasted, the stripping rate and the impurity removal effect of the materials are greatly improved, the waste gas discharge is reduced, and the method is more environment-friendly.
3. The compound structure enables the materials to flow from one end to the other end and undergo hot air preheating, multi-stage roasting and twice heat exchange, wherein the hot air preheating, the multi-stage roasting and the twice heat exchange are obtained through heat exchange, the discharging temperature is lower than 300 ℃, the temperature rising speed of the furnace temperature is high, the roasting temperature of the materials is lower than 30 minutes, the discharged waste gas temperature is low, the harmful substances are few, the generated energy consumption is lower, and the environment is more environment-friendly.
Drawings
FIG. 1 is a schematic side view of a multiple roasting apparatus according to the present invention;
FIG. 2 is a schematic top view of the multiple roasting apparatus of the present invention;
FIG. 3 is a cross-sectional view taken along line B-B of FIG. 1;
FIG. 4 is a cross-sectional view of C-C of FIG. 2;
FIG. 5 is a cross-sectional view A-A of FIG. 1;
FIG. 6 is a schematic perspective view of a multiple roasting apparatus according to the present invention;
the reference numerals in the figures mean: 1. the device comprises a driving motor, a material receiving groove, a vane wheel, a material inlet, a material feeding protection device, a casing, a shell, a heat preservation rock wool, a refractory brick, a hot air bellow, a hood, a maintenance manhole, a combustion gun, a horizontal combustion chamber, a wind separation impurity removal chamber, a heat exchange chamber, a second air outlet, a second air inlet, a wind nozzle, a spiral heat exchange pipe, a wind preheating chamber, a cold air, a wind box, a third air inlet, a discharge pipe, a material receiving hopper, a discharge hole, a pneumatic blowing system, a first air outlet, a pneumatic blowing system, a first air inlet, a second air inlet, a first air inlet, a support seat and a second air inlet, wherein the driving motor, the.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings, but the scope of the present invention is not limited to the embodiments.
Example 1:
a method for recycling waste foundry sand based on compound roasting equipment comprises the following steps:
s1, feeding materials into a receiving tank through a material homogenizing plate (not shown in the attached drawing), feeding the materials into a feeding protection device through an impeller, and feeding the materials into a combustion chamber of a horizontal combustion chamber;
s2, blowing the materials to boil by hot air at the bottom of the combustion chamber, flowing from the combustion chamber to the air separation impurity removal chamber, and sequentially carrying out three-stage roasting by a combustion gun in the period, wherein the temperature of the first-stage roasting is 300 ℃ and the time is 10 s; the temperature of the secondary roasting is 600 ℃, and the time is 240 s; the temperature of the third-stage roasting is 850 ℃ and the time is 10 s;
s3, after the material is roasted, the material falls into an air preheating chamber from an air separation impurity removal chamber, exchanges heat with cold air of a spiral heat exchange tube in the air preheating chamber and is cooled to 200 ℃, then the material is discharged, hot air exchanged by the spiral heat exchange tube is blown into the air separation impurity removal chamber through a blast nozzle, the roasted material is in a boiling state, and the friction between the material and the material is increased to achieve the effect of further removing the impurities; waste gas generated by roasting the materials is discharged after exchanging heat with cold air of a heat exchanger at the upper part of the air preheating chamber and cooling, and hot air exchanged by the heat exchanger enters a hot air bellows.
The compound roasting equipment is provided with a horizontal combustion chamber, the horizontal combustion chamber is divided into a combustion chamber and a wind selection impurity removal chamber, and the combustion chamber and the wind selection impurity removal chamber are mutually and transversely communicated;
a feeding mechanism is arranged at one end of the combustion chamber, which is far away from the air separation impurity removal chamber, and the feeding mechanism is used for conveying materials into the combustion chamber; a plurality of combustion guns are arranged on the side surface of the combustion chamber, and the combustion guns jet combustion flame towards the inside of the combustion chamber; a plurality of air caps are arranged at the bottom of the combustion chamber, the lower ends of the air caps are communicated with a hot air bellow, the hot air bellow comprises a first air inlet, and hot air enters the hot air bellow from the first air inlet and then is blown into the combustion chamber through the air caps;
a heat exchange chamber is communicated above the air separation impurity removal chamber, a first air outlet is formed in the upper end of the heat exchange chamber, and high-temperature waste gas generated after roasting enters the heat exchange chamber and is discharged from the first air outlet; a heat exchanger is arranged in the heat exchange chamber, and a plurality of heat exchange tubes are arranged on the heat exchanger; the heat exchanger comprises a second air inlet and a second air outlet, cold air enters the heat exchanger from the second air inlet, and is changed into hot air after exchanging heat with high-temperature waste gas and then is discharged from the second air outlet; the second air outlet is connected with the first air inlet, and hot air of the second air outlet enters the hot air bellows from the first air inlet;
the lower part of the air separation impurity removal chamber is communicated with an air preheating chamber, the lower end of the air preheating chamber is provided with a discharge pipe, and roasted high-temperature materials fall into the air preheating chamber, are discharged through the discharge pipe at the lower end of the air preheating chamber, fall into a material receiving hopper and are discharged from a discharge port; the air preheating chamber is internally provided with a plurality of spiral heat exchange tubes, the upper ends of the spiral heat exchange tubes are provided with air nozzles, the lower ends of the spiral heat exchange tubes are communicated with a cold air bellow, the cold air bellow comprises a third air inlet, cold air sequentially enters the cold air bellow and the spiral heat exchange tubes from the third air inlet, and after the cold air is subjected to heat exchange with roasted high-temperature materials through the spiral heat exchange tubes in the air preheating chamber, the cold air is blown into the air separation impurity removal chamber from the.
The heat exchanger is communicated above the air preheating chamber, high-temperature hot air rises due to negative pressure generated by an air outlet at the top of the heat exchanger, and exchanges heat with cold air blown in from the heat exchanger, so that the cold air is preheated; the preheated hot air is supplied to the combustion chamber for use. And a heat insulation layer is arranged outside the heat exchange chamber.
The combustion chamber and the air separation and impurity removal chamber are heated until the roasting temperature of the materials is lower than 30 minutes.
Example 2:
a method for recycling waste foundry sand based on compound roasting equipment comprises the following steps:
s1, feeding materials into a receiving tank through a material homogenizing plate (not shown in the attached drawing), feeding the materials into a feeding protection device through an impeller, and feeding the materials into a combustion chamber of a horizontal combustion chamber;
s2, blowing and boiling the material by hot air at the bottom of the combustion chamber, flowing from the combustion chamber to the air separation and impurity removal chamber, and sequentially carrying out three-stage roasting by a combustion gun in the period, wherein the temperature of the first-stage roasting is 400 ℃ and the time is 20 s; the temperature of the secondary roasting is 800 ℃, and the time is 180 s; the temperature of the three-stage roasting is 900 ℃ and the time is 20 s;
s3, after the material is roasted, the material falls into an air preheating chamber from an air separation impurity removal chamber, exchanges heat with cold air of a spiral heat exchange tube in the air preheating chamber and is cooled to 300 ℃, then the material is discharged, hot air exchanged by the spiral heat exchange tube is blown into the air separation impurity removal chamber through a blast nozzle, the roasted material is in a boiling state, and the friction between the material and the material is increased to achieve the effect of further removing the impurities; waste gas generated by roasting the materials is discharged after exchanging heat with cold air of a heat exchanger at the upper part of the air preheating chamber and cooling, and hot air exchanged by the heat exchanger enters a hot air bellows.
The compound roasting equipment is provided with a horizontal combustion chamber, the horizontal combustion chamber is divided into a combustion chamber and a wind selection impurity removal chamber, and the combustion chamber and the wind selection impurity removal chamber are mutually and transversely communicated;
a feeding mechanism is arranged at one end of the combustion chamber, which is far away from the air separation impurity removal chamber, and the feeding mechanism is used for conveying materials into the combustion chamber; a plurality of combustion guns are arranged on the side surface of the combustion chamber, and the combustion guns jet combustion flame towards the inside of the combustion chamber; a plurality of air caps are arranged at the bottom of the combustion chamber, the lower ends of the air caps are communicated with a hot air bellow, the hot air bellow comprises a first air inlet, and hot air enters the hot air bellow from the first air inlet and then is blown into the combustion chamber through the air caps;
a heat exchange chamber is communicated above the air separation impurity removal chamber, a first air outlet is formed in the upper end of the heat exchange chamber, and high-temperature waste gas generated after roasting enters the heat exchange chamber and is discharged from the first air outlet; a heat exchanger is arranged in the heat exchange chamber, and a plurality of heat exchange tubes are arranged on the heat exchanger; the heat exchanger comprises a second air inlet and a second air outlet, cold air enters the heat exchanger from the second air inlet, and is changed into hot air after exchanging heat with high-temperature waste gas and then is discharged from the second air outlet; the second air outlet is connected with the first air inlet, and hot air of the second air outlet enters the hot air bellows from the first air inlet;
the lower part of the air separation impurity removal chamber is communicated with an air preheating chamber, the lower end of the air preheating chamber is provided with a discharge pipe, and roasted high-temperature materials fall into the air preheating chamber, are discharged through the discharge pipe at the lower end of the air preheating chamber, fall into a material receiving hopper and are discharged from a discharge port; the air preheating chamber is internally provided with a plurality of spiral heat exchange tubes, the upper ends of the spiral heat exchange tubes are provided with air nozzles, the lower ends of the spiral heat exchange tubes are communicated with a cold air bellow, the cold air bellow comprises a third air inlet, cold air sequentially enters the cold air bellow and the spiral heat exchange tubes from the third air inlet, and after the cold air is subjected to heat exchange with roasted high-temperature materials through the spiral heat exchange tubes in the air preheating chamber, the cold air is blown into the air separation impurity removal chamber from the.
The side wall and the top of the combustion chamber and the air separation impurity removal chamber are sequentially provided with a high-temperature-resistant and wear-resistant material, a heat insulation layer and a shell from inside to outside.
Example 3:
a method for recycling waste foundry sand based on compound roasting equipment is characterized by comprising the following steps:
s1, feeding materials into a receiving tank through a material homogenizing plate (not shown in the attached drawing), feeding the materials into a feeding protection device through an impeller, and feeding the materials into a combustion chamber of a horizontal combustion chamber;
s2, blowing the materials to boil by hot air at the bottom of the combustion chamber, flowing from the combustion chamber to the air separation impurity removal chamber, and sequentially carrying out three-stage roasting by a combustion gun in the period, wherein the temperature of the first-stage roasting is 400 ℃ and the time is 15 s; the temperature of the secondary roasting is 700 ℃ and the time is 240 s; the temperature of the third-stage roasting is 850 ℃ and the time is 10 s;
s3, after the material is roasted, the material falls into an air preheating chamber from an air separation impurity removal chamber, exchanges heat with cold air of a spiral heat exchange tube in the air preheating chamber and is cooled to 250 ℃, then the material is discharged, hot air exchanged by the spiral heat exchange tube is blown into the air separation impurity removal chamber through a blast nozzle, the roasted material is in a boiling state, and the friction between the material and the material is increased to achieve the effect of further removing the impurities; waste gas generated by roasting the materials is discharged after exchanging heat with cold air of a heat exchanger at the upper part of the air preheating chamber and cooling, and hot air exchanged by the heat exchanger enters a hot air bellows.
The compound roasting equipment is provided with a horizontal combustion chamber, the horizontal combustion chamber is divided into a combustion chamber and a wind selection impurity removal chamber, and the combustion chamber and the wind selection impurity removal chamber are mutually and transversely communicated;
a feeding mechanism is arranged at one end of the combustion chamber, which is far away from the air separation impurity removal chamber, and the feeding mechanism is used for conveying materials into the combustion chamber; a plurality of combustion guns are arranged on the side surface of the combustion chamber, and the combustion guns jet combustion flame towards the inside of the combustion chamber; a plurality of air caps are arranged at the bottom of the combustion chamber, the lower ends of the air caps are communicated with a hot air bellow, the hot air bellow comprises a first air inlet, and hot air enters the hot air bellow from the first air inlet and then is blown into the combustion chamber through the air caps;
a heat exchange chamber is communicated above the air separation impurity removal chamber, a first air outlet is formed in the upper end of the heat exchange chamber, and high-temperature waste gas generated after roasting enters the heat exchange chamber and is discharged from the first air outlet; a heat exchanger is arranged in the heat exchange chamber, and a plurality of heat exchange tubes are arranged on the heat exchanger; the heat exchanger comprises a second air inlet and a second air outlet, cold air enters the heat exchanger from the second air inlet, and is changed into hot air after exchanging heat with high-temperature waste gas and then is discharged from the second air outlet; the second air outlet is connected with the first air inlet, and hot air of the second air outlet enters the hot air bellows from the first air inlet;
the lower part of the air separation impurity removal chamber is communicated with an air preheating chamber, the lower end of the air preheating chamber is provided with a discharge pipe, and roasted high-temperature materials fall into the air preheating chamber, are discharged through the discharge pipe at the lower end of the air preheating chamber, fall into a material receiving hopper and are discharged from a discharge port; the air preheating chamber is internally provided with a plurality of spiral heat exchange tubes, the upper ends of the spiral heat exchange tubes are provided with air nozzles, the lower ends of the spiral heat exchange tubes are communicated with a cold air bellow, the cold air bellow comprises a third air inlet, cold air sequentially enters the cold air bellow and the spiral heat exchange tubes from the third air inlet, and after the cold air is subjected to heat exchange with roasted high-temperature materials through the spiral heat exchange tubes in the air preheating chamber, the cold air is blown into the air separation impurity removal chamber from the.
And a maintenance inlet hole is formed in the side face of one end, far away from the air separation impurity removal chamber, of the combustion chamber.
And a part of the discharge pipe, which is positioned in the material receiving hopper, is provided with a pneumatic blowing system, and the pneumatic blowing system blows air from the inside of the discharge pipe towards the outlet direction of the discharge pipe.
Comparative example 1:
the vertical roasting furnace is adopted to recycle the casting waste sand, the temperature is raised to the roasting temperature for 90-120 minutes, the discharging temperature is 500-600 ℃, the temperature of the discharged waste gas is high, and the content of harmful substances is high.
Comparative example 2:
compared with the embodiment 1, the three-stage roasting process is not adopted, the roasting is directly carried out for one time, because the materials and the waste gas are not fully combusted, the film removing rate and the impurity removing effect of the materials are obviously reduced, and the content of harmful substances in the generated waste gas is high.
Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and variations of the present invention should fall within the scope of the claims of the present invention. In addition, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims (10)
1. A method for recycling waste foundry sand based on compound roasting equipment is characterized in that,
the compound roasting equipment is provided with a horizontal combustion chamber, the horizontal combustion chamber is divided into a combustion chamber and a wind selection impurity removal chamber, and the combustion chamber and the wind selection impurity removal chamber are mutually and transversely communicated;
a feeding mechanism is arranged at one end of the combustion chamber, which is far away from the air separation impurity removal chamber, and the feeding mechanism is used for conveying materials into the combustion chamber; a plurality of combustion guns are arranged on the side surface of the combustion chamber, and the combustion guns jet combustion flame towards the inside of the combustion chamber; a plurality of air caps are arranged at the bottom of the combustion chamber, the lower ends of the air caps are communicated with a hot air bellow, the hot air bellow comprises a first air inlet, and hot air enters the hot air bellow from the first air inlet and then is blown into the combustion chamber through the air caps;
a heat exchange chamber is communicated above the air separation impurity removal chamber, a first air outlet is formed in the upper end of the heat exchange chamber, and high-temperature waste gas generated after roasting enters the heat exchange chamber and is discharged from the first air outlet; a heat exchanger is arranged in the heat exchange chamber, and a plurality of heat exchange tubes are arranged on the heat exchanger; the heat exchanger comprises a second air inlet and a second air outlet, cold air enters the heat exchanger from the second air inlet, and is changed into hot air after exchanging heat with high-temperature waste gas and then is discharged from the second air outlet; the second air outlet is connected with the first air inlet, and hot air of the second air outlet enters the hot air bellows from the first air inlet;
the lower part of the air separation impurity removal chamber is communicated with an air preheating chamber, the lower end of the air preheating chamber is provided with a discharge pipe, and roasted high-temperature materials fall into the air preheating chamber, are discharged through the discharge pipe at the lower end of the air preheating chamber, fall into a material receiving hopper and are discharged from a discharge port; a plurality of spiral heat exchange tubes are arranged in the air preheating chamber, the upper ends of the spiral heat exchange tubes are provided with air nozzles, the lower ends of the spiral heat exchange tubes are communicated with a cold air bellow, the cold air bellow comprises a third air inlet, cold air sequentially enters the cold air bellow and the spiral heat exchange tubes from the third air inlet, and after heat exchange with roasted high-temperature materials through the spiral heat exchange tubes in the air preheating chamber, the cold air is blown into a winnowing impurity removal chamber from the air nozzles;
the method for recycling the waste foundry sand based on the duplex roasting equipment comprises the following steps:
s1, feeding materials into a receiving groove through a material homogenizing plate, feeding the materials into a feeding protection device through an impeller, and feeding the materials into a combustion chamber of a horizontal combustion chamber;
s2, blowing and boiling the material by hot air at the bottom of the combustion chamber, flowing from the combustion chamber to the air separation and impurity removal chamber, and sequentially carrying out three-stage roasting by a combustion gun in the period, wherein the temperature of the first-stage roasting is 300-400 ℃ and the time is 10-20 s; the temperature of the secondary roasting is 600-800 ℃, and the time is 180-240 s; the temperature of the three-stage roasting is 850-900 ℃, and the time is 10-20 s;
s3, after the material is roasted, the material falls into a wind preheating chamber from a wind separation impurity removal chamber, exchanges heat with cold wind of a spiral heat exchange tube in the wind preheating chamber and is cooled to 200-plus-300 ℃, then the material is discharged, hot wind exchanged by the spiral heat exchange tube is blown into the wind separation impurity removal chamber through a wind nozzle, the roasted material is in a boiling state, and the friction between the material and the material is increased to achieve the effect of further removing the impurities; waste gas generated by roasting the materials is discharged after exchanging heat with cold air of a heat exchanger at the upper part of the air preheating chamber and cooling, and hot air exchanged by the heat exchanger enters a hot air bellows.
2. The method for recycling foundry waste sand based on multiple roasting equipment as claimed in claim 1, wherein the temperature of the primary roasting is 400 ℃ and the time is 15 s; the temperature of the secondary roasting is 700 ℃ and the time is 240 s; the temperature of the three-stage roasting is 850 ℃ and the time is 10 s.
3. The method for recycling waste foundry sand based on multiple roasting equipment as claimed in claim 1, wherein the heat exchanger is communicated above the air preheating chamber, and due to the negative pressure generated by the air outlet at the top of the heat exchanger, the hot air with high temperature rises and exchanges heat with the cold air blown in by the heat exchanger, so that the cold air is preheated.
4. The method for recycling foundry waste sand based on multiple roasting equipment as claimed in claim 1, wherein the combustion chamber and the air separation and impurity removal chamber are raised to the roasting temperature of the materials for less than 30 minutes.
5. The method for recycling waste foundry sand based on multiple roasting equipment as claimed in claim 1, wherein an insulating layer is arranged outside the heat exchange chamber.
6. The method for recycling the foundry waste sand based on the duplex roasting equipment as claimed in claim 1, wherein the side walls of the combustion chamber and the air separation and impurity removal chamber are sequentially provided with a high-temperature-resistant and wear-resistant material, an insulating layer and a shell from inside to outside.
7. The method for recycling the foundry waste sand based on the multiple roasting equipment as claimed in claim 1, wherein the top of the combustion chamber and the air separation and impurity removal chamber is sequentially provided with a high-temperature-resistant and wear-resistant material, an insulating layer and a shell from inside to outside.
8. The method for recycling foundry waste sand based on a duplex roasting apparatus as claimed in claim 1, wherein a maintenance access hole is formed in the side surface of one end of the combustion chamber, which is far away from the air separation impurity removing chamber.
9. The method for recycling foundry waste sand based on a multiple roasting apparatus of claim 1, wherein the portion of the tapping pipe located in the receiving hopper is provided with a pneumatic blowing system, and the pneumatic blowing system blows air from the inside of the tapping pipe toward the outlet of the tapping pipe.
10. The method for recycling waste foundry sand based on multiple roasting equipment as claimed in claim 1, wherein the impeller is driven by a driving motor, the lower part of the impeller is a feed inlet, and a feed protection device is arranged between the feed inlet and the combustion chamber.
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| CN110252943A (en) * | 2019-06-12 | 2019-09-20 | 南通凯斯辛普森机械科技有限公司 | Antiquated sand thermal reclamation equipment and antiquated sand thermal reclamation technique |
| CN114562881B (en) * | 2022-03-01 | 2024-04-26 | 广西兰科资源再生利用有限公司 | Method for recycling foundry waste sand based on vertical energy-saving roasting furnace |
| CN114799043B (en) * | 2022-03-31 | 2024-01-26 | 广西兰科资源再生利用有限公司 | Energy-saving circulation system for grinding sand-to-sand heat exchange |
| CN114812183A (en) * | 2022-04-22 | 2022-07-29 | 驻马店市新创业管桩附件有限公司 | Precoated sand regenerating furnace capable of utilizing heat |
| CN115415477B (en) * | 2022-11-03 | 2023-03-24 | 托普工业(江苏)有限公司 | 3D prints casting sand mould recovery processing system |
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| JPS58159941A (en) * | 1982-03-17 | 1983-09-22 | Taiyo Chuki Kk | Method for regulating temperature of molding sand recovered from green sand mold in cooling drum |
| US6019157A (en) * | 1996-01-19 | 2000-02-01 | Kimura Chuzosho Co., Ltd. | Method of regenerating foundry sand |
| CN203091666U (en) * | 2013-01-18 | 2013-07-31 | 合肥市瑞宏铸造有限公司 | Foundry waste sand roasting regenerating furnace |
| CN205270722U (en) * | 2016-01-05 | 2016-06-01 | 临海市新特铸造机械有限公司 | Horizontal old sand bakes burning furnace over a slow fire |
| CN105499484B (en) * | 2016-01-08 | 2017-08-29 | 山东金璞新材料有限公司 | A kind of quick roasting regeneration system of energy-saving coil pipe cooled casting model powder |
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Denomination of invention: A method for recycling foundry waste sand based on compound roasting equipment Effective date of registration: 20220510 Granted publication date: 20200110 Pledgee: Bank of Guilin Co.,Ltd. Yulin Branch Pledgor: GUANGXI LANCO RESOURCES RECYCLING CO.,LTD. Registration number: Y2022450000069 |
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