CN112815709A

CN112815709A - Fluidized roasting method

Info

Publication number: CN112815709A
Application number: CN202011623315.3A
Authority: CN
Inventors: 熊帆; 熊鹰; 王德春; 陈方旭; 周高胜
Original assignee: Chongqing Changjiang River Moulding Material Group Co ltd
Current assignee: Chongqing Changjiang River Moulding Material Group Co ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-05-18

Abstract

The invention relates to the technical field of casting material treatment, and discloses a fluidized roasting method which is used in combination with a roasting furnace and comprises the following steps: (1) sealing a discharge hole of the roasting furnace in a self-sealing mode; (2) starting the burner to raise the temperature inside the furnace body; (3) roasting: adding waste sand into the furnace body for roasting; (4) adjusting the temperature: controlling the start or the stop of the burner according to the pressure and the temperature in the roasting furnace, and further adjusting the temperature in the furnace body; (5) and cooling and discharging the sand in the furnace body. The fluidized roasting method can improve the energy utilization efficiency and achieve the effect of energy conservation.

Description

Fluidized roasting method

Technical Field

The invention relates to the technical field of casting material treatment, in particular to a fluidized roasting method.

Background

The roasting furnace is a main device for the hot method regeneration technology of the waste foundry sand, and the waste foundry sand is roasted at high temperature to enable a film coating layer on the surface of the waste foundry sand to fall off, so that the waste foundry sand is regenerated and recycled.

The roasting furnace commonly used at present is a vertical two-layer roasting furnace, the upper part of the furnace body is connected with a feed inlet, a sealing plate is arranged in the furnace body, the sealing plate divides the furnace body into an upper combustion chamber and a lower combustion chamber, the bottom of the furnace body is connected with a discharge pipe and communicated with a main pipe, and a combustor is arranged in the main pipe. The specific flow of the roasting furnace during operation is as follows: add waste sand through the inlet pipe toward last combustion chamber, waste sand flows on the shrouding, then falls into in the combustion chamber down in proper order, discharges through arranging the material pipe at last to this is simultaneously, and the air in the combustor heating main pipe makes the air temperature rise, is responsible for and lets in red-hot air in down the combustion chamber, and red-hot air heats waste sand. In the process, air flows from the lower combustion chamber to the upper combustion chamber in sequence and is finally discharged through the feeding pipe; when air flows from the lower combustion chamber to the upper combustion chamber, two paths are provided, wherein the first path directly flows to the upper combustion chamber through the sealing plate, and the second path is opposite to the flow direction of the waste sand.

However, the roasting furnace in the prior art has low thermal efficiency and consumes more energy in the use process.

Disclosure of Invention

The invention aims to provide a fluidized roasting method, which can improve the energy utilization efficiency and achieve the effect of energy conservation.

In order to achieve the purpose, the invention adopts the following technical scheme: a fluidized roasting method used in combination with a roasting furnace comprises the following steps:

(1) sealing a discharge hole of the roasting furnace in a self-sealing mode;

(2) starting the burner to raise the temperature inside the furnace body;

(3) roasting: adding waste sand into the furnace body for roasting;

(4) adjusting the temperature: controlling the start or the stop of the burner according to the pressure and the temperature in the roasting furnace, and further adjusting the temperature in the furnace body;

(5) and cooling and discharging the sand in the furnace body.

The principle and the beneficial effect of this scheme of adoption lie in: many enterprises have to solve the problem of high energy consumption of the roasting furnace, and the reason is that the large energy consumption is caused by a miszone. The inventor researches for many years and creatively discovers the reason of influencing the energy consumption of the roasting furnace.

Through years of research, the inventor finds that sand feeding and sand discharging are performed substantially simultaneously in the roasting process of the furnace body in the prior art, and during the sand feeding process, especially the sand discharging process, air is discharged along the flowing direction of the sand discharging process, so that heat loss is caused.

It is based on the inventors' creative discovery of the existing problems that the present solution was invented to solve the above problems. This scheme adopts the self sealss mode earlier to seal over a slow fire burning furnace before the calcination to at the calcination in-process, prevent that the heat in the furnace body from discharging along with the sand discharge, thereby reached and improved energy utilization efficiency, reached energy-conserving effect.

Experiments show that the energy consumption of the pyrolysis furnace adopting the scheme is reduced by about 40-60% compared with the original energy consumption.

Further, step (4) includes the following substeps:

1) detecting the temperature in the first roasting chamber through a temperature sensor;

2) controlling ignition/flameout of the combustor according to the detection result of the temperature sensor;

3) detecting pressure values in the first roasting chamber and the second roasting chamber;

4) and controlling the opening of the first valve according to the pressure values and the temperatures of the first roasting chamber and the second roasting chamber.

Further, the middle part of the furnace body is provided with a sealing plate, the sealing plate divides the furnace body into a first cavity and a second cavity, a combustion mechanism is arranged in the first cavity, the upper end of the furnace body is provided with a feeding mechanism, the feeding mechanism is communicated with the first cavity, a sand discharging structure is arranged in the second cavity, the lower part of the furnace body is provided with an air source and an air chamber, the air chamber is communicated with the air source, the air chamber is communicated with the second cavity, the sealing plate is provided with a plurality of communicating parts for communicating the first cavity with the second cavity, and a waste heat recovery part is arranged in.

Further, the communicating part comprises a first communicating pipe and a second communicating pipe, the first communicating pipe and the second communicating pipe are perpendicular and communicated, the first communicating pipe penetrates through the sealing plate, the lower end of the first communicating pipe is located in the second chamber, and the second communicating pipe is horizontally arranged and the two ends of the second communicating pipe are respectively provided with a seal.

Further, feed structure includes the inlet pipe, and the vertical setting of inlet pipe and one end and first cavity intercommunication are the feed inlet on the inlet pipe, are equipped with partial sand portion on inlet pipe upper portion.

Further, the quantity of waste heat recovery portion is a plurality of, and a plurality of waste heat recovery portions follow the inlet pipe and from last down evenly set up.

Further, the temperature control range in the first roasting chamber is 550-700 ℃.

Drawings

FIG. 1 is a schematic view of a roaster according to an embodiment of the present invention;

FIG. 2 is an enlarged view of FIG. 1;

FIG. 3 is an enlarged view at C in FIG. 2;

FIG. 4 is an enlarged view of FIG. 1 at B;

FIG. 5 is an enlarged view of FIG. 4 at D;

FIG. 6 is a schematic structural view of a roasting furnace in a second embodiment of the fluidized roasting method of the present invention;

FIG. 7 is an enlarged view at E of FIG. 6;

fig. 8 is an enlarged view at F in fig. 6.

Detailed Description

The following is further detailed by way of specific embodiments:

reference numerals in the drawings of the specification include: the device comprises a furnace body 1, a first chamber 2, a sealing plate 3, a second chamber 4, an air chamber 5, a feeding pipe 6, a first recovery piece 7, a second recovery piece 8, a supporting rod 9, a burner 10, a fan 11, an observation window 12, a communicating pipe 13, a hood 14, a blowing port 15, a sand discharge pipe 16, a sand discharge cavity 17, an air cavity 18, an outer pipe 19, an inner pipe 20, a communicating cavity 21, an air outlet 22, an accommodating cavity 23, a motor 24, a connecting plate 25, a nut 26, a supporting ring 27, a rotating shaft 28, a first bevel gear 29, a second bevel gear 30, a screw rod 31, a tightening rod 32, a rotating ring 33 and a sealing box 34.

Example one

This embodiment is substantially as shown in figure 1: including

furnace body

1, 1 middle part of furnace body is equipped with horizontal shrouding 3, and shrouding 3 is separated furnace body 1 for first cavity 2 and second cavity 4, is equipped with combustion mechanism in the 2 first cavities, and combustion mechanism in this embodiment is

combustor

10, and 1 lateral wall of furnace body still is equipped with observation window 12. The upper end of the furnace body 1 is provided with a feeding mechanism, the feeding mechanism is communicated with the first cavity 2, and a sand discharge structure is arranged in the second cavity 4. The lateral part of the furnace body is provided with a sand discharge mechanism which is communicated with the first cavity and the second cavity. The lower part of the furnace body 1 is provided with an air source and an air chamber 5, and the air chamber 5 is communicated with the air source. The air source in this embodiment is a fan 11, and the fan 11 is fixedly connected with the furnace body 1 through bolts. The air chamber 5 is communicated with the second chamber 4, a plurality of communicating parts for communicating the first chamber 2 with the second chamber 4 are arranged on the sealing plate 3, and a waste heat recovery part is arranged in the feeding structure.

The plurality of communicating portions are uniformly provided along the closing plate 3. The communicating part comprises a communicating pipe 13 and a blast cap 14, the communicating pipe 13 and the blast cap 14 are perpendicular and communicated, the communicating pipe 13 penetrates through the sealing plate 3, the lower end of the communicating pipe is located in the second chamber 4, and the blast cap 14 is horizontally arranged and two ends of the blast cap are respectively provided with a blowing port 15.

The feeding structure comprises a feeding pipe 6, wherein the feeding pipe 6 is vertically arranged, one end of the feeding pipe is communicated with the first cavity 2, the upper end of the feeding pipe 6 is a feeding hole, and a sand separation part is arranged on the upper part of the feeding pipe 6. The sand separating part comprises a plurality of sand separating rods which are arranged side by side, and a gap is arranged between every two adjacent sand separating rods. The quantity of waste heat recovery portion is a plurality of, and a plurality of waste heat recovery portions follow inlet pipe 6 and from last down evenly set up. The waste heat recovery part comprises a first recovery part 7 and a second recovery part 8, the first recovery part 7 and the second recovery part 8 are respectively connected with the inner wall of the feeding pipe 6, the first recovery part 7 is conical and is positioned at the upper end of the second recovery part 8, the second recovery part 8 is in an inverted frustum shape, and the area of the upper end of the second recovery part 8 is larger than that of the lower end of the first recovery part 7. The first and

second recovery members

7 and 8 are connected to the feed pipe 6 by a support rod 9.

The sand discharge mechanism comprises a closed box 34 and a sand discharge pipe 16, and the sand discharge pipe 16 is communicated with the lower part of the closed box 34; the sand discharge pipe 16 is provided with a partition board along the length direction, the partition board divides the sand discharge pipe 16 into a sand discharge cavity 17 and an air cavity 18, the air cavity 18 is communicated with an air source, a plurality of air discharge parts are arranged in the sand discharge cavity 17, each air discharge part comprises an outer pipe 19 and an inner pipe 20, the upper end of the outer pipe 19 is sealed, the inner pipe 19 is communicated with a cavity 21, the inner pipe 20 is positioned in the outer pipe 19, two ends of the inner pipe 20 are respectively communicated with the outer pipe 19 and the air cavity 18, and the side part of the outer pipe 19 is provided; the length of the sand drain 16 is more than three times the height of the sand drain 16.

The method comprises the following steps:

(1) sealing a discharge hole of the roasting furnace in a self-sealing mode;

(2) starting the burner to raise the temperature inside the furnace body;

(3) roasting: adding waste sand into the furnace body for roasting;

(5) and cooling and discharging the sand in the furnace body.

In the step (4), the following substeps are included:

When the roasting furnace in the scheme is used, the first chamber 2 is a combustion chamber, and after the waste sand enters the combustion chamber, the combustion machine 10 in the first chamber 2 is ignited to combust the waste sand. While the lower air chamber feeds air into the second chamber 4. The cool air enters the second chamber 4 and contacts the sand in the second chamber 4. At the moment, the flow direction of the cold air is vertical to the flow direction of the waste sand, and the air is in direct contact with the sand instead of conducting, so that the heat exchange efficiency of the air and the sand can be improved, the energy utilization rate is improved, and the energy-saving effect is achieved.

During the flow, the sand enters the closed box 34 and flows from the closed box 34 to the sand discharge chamber 17. Because the length of the sand discharge cavity 17 is more than three times of the height of the sand discharge pipe 16, the angle of a diagonal line formed by the sand discharge pipe 16 is less than the repose angle of sand, when the sand flows from the closed box 34 to the end part of the sand discharge pipe 16 close to the closed box 34, the sand cannot naturally flow and flows out of the sand discharge pipe 16, namely the sand is accumulated when entering the sand discharge pipe 16, the granularity of the sand is small, namely the gap between the sand is very small, the sand accumulation at the conveying part can play a self-sealing role on the conveying part, the air is prevented from reversely flowing along the conveying part, the air can only flow according to an expected route, and the sand discharge effect is achieved. When the sand needs to be discharged from the conveying part, the air source is started, the air source generates air, and the air generated by the air source enters the air cavity 18, enters the inner pipe 20 through the air cavity 18 and enters the outer pipe 19 through the inner pipe 20. Because the upper end of the outer pipe 19 is closed and the side part is provided with the air outlet 22, the air can only blow out from the air outlet 22 on the side wall of the lower part of the outer pipe 19 and blow sand to flow along the sand discharge pipe 16, and the sand discharge effect is achieved. In the process, sand is still accumulated at the end part of the sand discharge pipe 16, so that the self-sealing effect is achieved.

After the furnace body 1 is sealed by sand in the furnace body 1, air in the second chamber 4 can only flow upwards to enter the first chamber 2. Namely, the air flows upwards along the communicating pipe 13, enters the blast cap 14 after entering the communicating pipe 13, and flows out from the air outlet at the side part of the blast cap 14. The air outlet is arranged on the side part of the blast cap 14, so that sand can be prevented from entering the blast cap 14. Air flows out of the outlet opening into the first chamber 2 and from the first chamber 2 into the feed tube 6, and flows up the feed tube 6. The air contacts with the first and

second recovery members

7 and 8 during the upward movement along the feeding pipe 6, so that the temperature of the first and

second recovery members

7 and 8 is increased, and the conical shape of the first recovery member 7 can increase the contact area with the air, so that the heat exchange effect is improved. When the sand enters the furnace body 1 from the feeding pipe 6, the sand is contacted with the first recovery piece 7 and the second recovery piece 8, so that the temperature of the sand is increased, and the energy-saving effect is achieved.

Experiments show that the energy consumption of the pyrolysis furnace adopting the scheme is reduced by about 40-60% compared with the original energy consumption, and the roasting efficiency is reduced by about 60-70%.

Example two

Referring to fig. 6, 7 and 8, the present embodiment is different from the first embodiment in that the present embodiment further includes a sand discharge device. The sand discharge device comprises a sand scraping plate, a screw rod 31, a rotating ring 33 and a threaded part, the sand scraping plate, the screw rod 31 and the threaded part are all located in the second chamber 4, and the number of the rotating ring and the number of the threaded part are two. The screw 31 is transversely arranged and is rotationally connected with the side wall of the second chamber 4 through a bearing, and the screw is in threaded fit with the screw 31. The threaded member in this embodiment is a nut 26. The sand scraping plate comprises a first connecting plate and a second connecting plate 25, the end parts of the first connecting plate and the second connecting plate 25 are hinged through connecting pins, and the left end of the screw rod 31 is a polished rod. The rotary ring 33 is rotationally engaged with the screw 31. The end of the first connecting plate remote from the second connecting plate 25 is hinged to the left swivel ring 33, and the end of the second connecting plate 25 remote from the first connecting plate is hinged to the right swivel ring 33. The rotating ring 33 is coaxially connected with the screw member and is rotatably engaged with the screw member. And a tight supporting rod 32 for limiting the rotation of the threaded part is further arranged in the second chamber 4, and the left end and the right end of the tight supporting rod are respectively hinged with a tight supporting rod.

An accommodating cavity 23 is arranged on the right side of the furnace body 1 where the second cavity 4 is positioned, and a power source is positioned in the accommodating cavity 23. The power source in this embodiment is a motor 24. Also included in this embodiment is a shaft 28, a first bevel gear 29 and a second bevel gear 30. The output shaft of the motor 24 is coaxially and fixedly connected with one end of a rotating shaft 28, and the other end of the rotating shaft 28 is connected with a first bevel gear 29. A support ring 27 is further provided in the receiving cavity, and a rotating shaft 28 passes through the support ring 27 and is rotatably connected with the support ring 27 through a bearing. A second bevel gear 30 is located in the receiving chamber 23 and is rotatably connected to the receiving chamber 23, the first bevel gear 29 being engaged with the second bevel gear 30. The second bevel gear 30 is coaxially connected to the screw 31.

The end surface of the sand scraping plate is evenly provided with a plurality of air holes, so that air can conveniently enter the first cavity 2.

When the sand is roasted, the first connecting plate and the second connecting plate 25 are in a horizontal state and the horizontal planes of the first connecting plate and the second connecting plate 25 are the same. The sand scraping plate can not influence the normal roasting of the sand. When the sand needs to be discharged, the motor 24 is started, the motor 24 rotates and drives the rotating shaft 28 to rotate, and the rotating shaft 28 rotates and drives the first bevel gear 29 to rotate. Since the first bevel gear 29 and the second bevel gear 30 are engaged, rotation of the first bevel gear 29 causes rotation of the second bevel gear 30. The screw 31 coaxially connected with the second bevel gear 30 rotates. At this moment, make the tight branch of support of right-hand member parallel with the tight pole of support, the tight branch of support of left end upwards rotates, because screw member and screw rod 31 screw-thread fit, so the screw rod 31 screw-in under the effect of tight pole and the tight branch of support when rotating right-hand member, and move left along screw rod 31, two screw members are close to promptly, the angle change of the articulated department of first connecting plate and second connecting plate 25, move the screw member department of left end until the screw member, first connecting plate and second connecting plate 25 offset and be vertical state this moment, and the screw member of left end can rotate along with the screw rod because do not contact with the tight branch of support. Then the abutting support rod at the left end is parallel to the abutting rod, the motor 24 is started to rotate reversely, the screw rod 31 is driven to rotate reversely when the motor 24 rotates reversely, and the threaded part moves reversely along the screw rod 31 under the action of the abutting rod and the abutting support rod. During the reverse movement of the screw 31 along the screw members, the two screw members move together, i.e. the scraper moves from left to right along the second chamber 4 at this time, scraping the sand out of the second chamber 4.

The inventors have also found that one reason for the high energy consumption of the prior art roasting furnaces is that the prior art roasting furnaces have a high energy consumption at start-up, especially at cold furnace start-up. Because the sand in the furnace body can not be completely discharged after the roasting of the roasting furnace in the prior art is completed for one time, a part of the sand is remained at the bottom of the furnace body. When the furnace is started, the temperature in the furnace body reaches the corresponding temperature (about 600 ℃), and the sand at the bottom of the furnace body is heated to the corresponding temperature, so that the energy consumption is high. In this scheme, can discharge the sand in the furnace body bottom as far as possible through setting up sand discharging device, reduce the energy consumption when thermal cracking furnace cold start, shorten the start-up time.

The foregoing is merely an example of the present invention and common general knowledge in the art of designing and/or characterizing particular aspects and/or features is not described in any greater detail herein. It should be noted that, for those skilled in the art, without departing from the technical solution of the present invention, several variations and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.

Claims

1. A fluidized roasting method is used by combining with a roasting furnace, and is characterized in that: the method comprises the following steps:

(1) sealing a discharge hole of the roasting furnace in a self-sealing mode;

(2) starting the burner to raise the temperature inside the furnace body;

(3) roasting: adding waste sand into the furnace body for roasting;

(5) and cooling and discharging the sand in the furnace body.

2. A fluidized roasting method as defined in claim 1, characterized in that: in the step (4), the following substeps are included:

3. A fluidized roasting method as defined in claim 2, characterized in that: the furnace body middle part is equipped with the shrouding, and the shrouding is separated the furnace body for first cavity and second cavity, is equipped with combustion mechanism in the first cavity, and the furnace body upper end is equipped with feed mechanism, and feed mechanism and first cavity intercommunication are equipped with the sand discharging structure in the second cavity, and the furnace body lower part is equipped with wind regime and plenum, plenum and wind regime intercommunication, plenum and second cavity intercommunication are equipped with the intercommunication portion of a plurality of first cavities of intercommunication and second cavity on the shrouding, are equipped with waste heat recovery portion in the feed structure.

4. A fluidized roasting method according to claim 3, characterized in that: the communicating part comprises a first communicating pipe and a second communicating pipe, the first communicating pipe and the second communicating pipe are perpendicular and communicated, the first communicating pipe penetrates through the sealing plate, the lower end of the first communicating pipe is located in the second chamber, the second communicating pipe is horizontally arranged, and two ends of the second communicating pipe are respectively provided with a seal.

5. The fluidized roasting method according to claim 4, wherein: the feeding structure comprises a feeding pipe, the feeding pipe is vertically arranged, one end of the feeding pipe is communicated with the first cavity, the upper end of the feeding pipe is a feeding port, and a sand separating part is arranged on the upper portion of the feeding pipe.

6. The fluidized roasting method of claim 5, wherein: the quantity of waste heat recovery portion is a plurality of, and a plurality of waste heat recovery portions follow the inlet pipe and from last down evenly set up.

7. The fluidized roasting method according to claim 6, wherein: the temperature control range in the first roasting chamber is 550-700 ℃.