Continuous furfural production process and device

Abstract

The invention aims to provide a continuous furfural production process and device, and belongs to the technical field of furfural production.The device comprises a stirrer, a discharging port of the stirrer is connected with a hydrolyzer through a feeding gun, a discharging port in the bottom of the hydrolyzer is connected with a slag discharger, a discharging port of the slag discharger is connected with a slag collector and a decompression tank, and the discharging port of the slag collector is connected with a discharging port of the decompression tank; a discharge hole of the pressure reducing tank is connected with a gas-slag separator, and the bottom of the gas-slag separator is connected with a slag discharge valve. The production process is continuous, a continuous reaction process is generated, and periodic cleaning is not needed.

Description

Technical Field

[0001] The invention belongs to the technical field of furfural production, and specifically relates to a continuous furfural production process and device. Background Art

[0002] Furfural is a compound organic substance, which is mainly produced by acid hydrolysis of pentosan to generate pentose, followed by dehydration and cyclization. At present, the raw materials for the production of furfural are mainly crops such as corn cobs. Its chemical properties are active and there are many derivatives. It can be widely used in medicine, plastics or agriculture. At the same time, it uses corn cobs, a "waste" crop, to produce benefits for environmental protection. In the production process of furfural, a hydrolysis kettle is used as a storage device for raw material reactions.

[0003] The hydrolysis process is the most important part of furfural production. The more typical hydrolysis process is the currently commonly used intermittent series hydrolysis process. After years of development, the hydrolysis pot has only been enlarged, and the intermittent process has many disadvantages: filling-pressurization-hydrolysis-emptying, the production process has been cyclical. This process has the following disadvantages: 1. Steam is consumed by increasing pressure, decreasing pressure and discharging the boiler; 2. When the boiler is discharged centrally, a large amount of harmful gases are difficult to recover, and the recycling and environmental protection equipment must be large enough (large equipment, large investment); 3. The environmental protection equipment is used when the pot is discharged, and it runs idle when the pot is not discharged, which consumes a lot of electricity; 4. It takes a certain amount of time for the hydrolysis pot to rise from normal pressure to the hydrolysis pressure, which is very likely to form resin and affect the yield of furfural; 5. It requires a large number of workers, making intermittent automation difficult to achieve and requiring a high level of labor intensity. Summary of the invention

[0004] In view of the problems existing in the existing intermittent hydrolysis of furfural hydrolysis, the present invention provides a continuous furfural production process and device.

[0005] The present invention adopts the following technical solution: A continuous furfural production process comprises the following steps: In the first step, the corn cob raw material is crushed by a crusher and transported to a mixer; In the second step, the prepared dilute sulfuric acid is sprayed into the mixer in proportion using a pump or a high-level tank to control the flow rate; The third step is to stir evenly and then squeeze the mixture into the hydrolyzer through a feed gun; Step 4: After the hydrolysis is completed, the slag is discharged into the gas-slag separator through the slag discharger, slag collector, and pressure reducing tank in sequence; The fifth step is to separate the gas and slag through the slag discharge valve at the bottom of the gas-slag separator. The slag is transported to the warehouse through a belt, and the gas passes through the deodorization system and is discharged after being treated as qualified.

[0006] Furthermore, the corn cob in the first step has a particle size of 1.5 cm after being crushed.

[0007] Furthermore, the mass concentration of the dilute sulfuric acid in the second step is 6.8%, and the mass ratio of corn cobs to dilute sulfuric acid is 3:1.

[0008] Furthermore, the pressure in the hydrolyzer is 0.8 MPa, the temperature is 170.44° C., and the hydrolysis time in the hydrolyzer is 180 min.

[0009] A continuous furfural production device comprises a mixer, wherein the mixer has a discharge port connected to a hydrolyzer through a feed gun, the discharge port at the bottom of the hydrolyzer is connected to a slag discharger, the discharge port of the slag discharger is connected to a slag collector and a pressure reducing tank, the discharge port of the pressure reducing tank is connected to a gas-slag separator, and the bottom of the gas-slag separator is connected to a slag discharge valve.

[0010] Furthermore, the hydrolyzer includes four horizontally placed reactors, which are connected in sequence from top to bottom. The reactors are provided with conveying stirring blades, the stirring blades are connected to a power rotating assembly, sealing assemblies and bearing brackets are provided at both ends of the reactors, and the reactors are equipped with radar level meters.

[0011] Furthermore, six sets of steam control valves are installed at equal intervals at the lower part of the reactor, and a steam and raw material crossing section and an aldehyde outlet are arranged at the top of the uppermost reactor.

[0012] Furthermore, the feed gun includes a cylinder barrel, which includes a stroke section, a feed section and an extrusion sealing section in sequence; a stroke switch is provided on the outside of the stroke section of the cylinder barrel, a feed port is provided at the top of the feed section of the cylinder barrel, and a preheating sleeve is provided on the outside of the extrusion sealing section of the cylinder barrel; a piston is provided in the cylinder barrel, one end of the piston is connected to an oil cylinder, the other end of the oil cylinder extends out of the cylinder barrel, a limiter is provided on the oil cylinder, and one end of the limiter passes through the stroke switch; a discharge port is provided at one end of the cylinder barrel close to the extrusion sealing section, the discharge port is connected to the feed port of the reactor, the oil cylinder is connected to the piston by a thread, one end of the oil cylinder is connected to a hydraulic oil station for providing a power source, and the inner diameter of the extrusion sealing section of the cylinder barrel gradually expands toward the discharge port.

[0013] Furthermore, the slag discharger includes a second cylinder barrel, a second piston moving along the second cylinder barrel is provided in the second cylinder barrel, one end of the second piston is connected to the second oil cylinder through a connecting rod, a second limiter is provided on the connecting rod, a second travel switch is provided at the top of the second cylinder barrel close to the second oil cylinder, the second limiter passes through the second travel switch, a second feed port is provided at the top of the second cylinder barrel away from the second oil cylinder, the second feed port is connected to the discharge port of the reactor, a slag discharge port is provided at the end of the second cylinder barrel away from the second oil cylinder, the slag discharge port is connected to the pressure reducing tank, a sealing section is provided in the middle of the second cylinder barrel, an exhaust port is provided at the top of the second cylinder barrel close to the sealing section, the exhaust port is close to the side of the slag discharge port, the connecting rod is connected to the second piston through a fixed frame, and a hydraulic oil station for providing power is provided at one end of the second oil cylinder.

[0014] Furthermore, the slag discharge valve includes a blade cylinder, an upper plugging plate and a lower plugging plate are respectively provided in the middle and bottom of the blade cylinder, the upper plugging plate and the lower plugging plate are respectively provided with openings, a rotating shaft is passed through the center of the blade cylinder, blades are provided on the rotating shaft, a sprocket is provided at the part of the rotating shaft located at the bottom of the blade cylinder, the sprocket is connected to a motor through a chain, the number of blades of the blade cylinder located at the upper part of the upper plugging plate is four, which are arranged alternately, the number of blades of the blade cylinder located at the lower part of the upper plugging plate is two, which are arranged symmetrically relative to the rotating shaft, the openings of the upper plugging plate and the lower plugging plate are arranged symmetrically, and the size of the opening does not exceed the size of one blade, the part of the rotating shaft located at the upper plugging plate is provided with a shaft sleeve bracket, a nylon sleeve is provided in the shaft sleeve bracket, a blade fixing frame is provided at the top of the shaft sleeve bracket, the rotating shaft is located at the bottom of the blade cylinder and is connected to a bearing through a bearing bracket, a stuffing box is provided in the bearing bracket, a dust guard plate is provided at the bottom of the bearing, the dust guard plate is sleeved on the rotating shaft, and a flange for connection is provided at the top of the blade cylinder.

[0015] The beneficial effects of the present invention are as follows: 1. The continuous production process of the present invention continuously adds the raw materials into the reactor in proportion and at a constant speed, and continuously discharges the reaction products from the reactor at a constant speed. This production method breaks through the limitations of kettle reactions and has higher production efficiency and better temperature control.

[0016] 2. The production process of the present invention is continuous, resulting in a continuous reaction process without the need for periodic cleaning.

[0017] 3. The production process of the present invention has a higher degree of automation and better control over reaction conditions and product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a continuous furfural production device of the present invention; Figure 2 It is a schematic diagram of the structure of the feed gun of the present invention; Figure 3 It is a schematic diagram of the structure of the slag discharger of the present invention; Figure 4 It is a schematic diagram of the structure of the slag discharge valve of the present invention; Among them: 1- mixer; 2- feed gun; 3- hydrolyzer; 4- slag discharger; 5- pressure reducing tank; 6- slag collector; 7- slag discharge valve; 8- cylinder barrel 1; 9- travel switch 1; 10- feed port 1; 11- preheating jacket; 12- piston 1; 13- oil cylinder 1; 14- stopper 1; 15- discharge port; 16- cylinder barrel 2; 17- piston 2; 18- connecting rod; 19- oil cylinder 2; 20- stopper 2; 21 -travel switch 2; 22-feed port 2; 23-slag discharge port; 24-sealing section; 25-exhaust port; 26-fixed frame; 27-blade cylinder; 28-upper plugging plate; 29-lower plugging plate; 30-rotating shaft; 31-blade; 32-sprocket; 33-sleeve bracket; 34-blade fixing frame; 35-bearing bracket; 36-bearing; 37-stuffing box; 38-dust shield; 39-flange; 40-gas-slag separator. DETAILED DESCRIPTION

[0019] The present invention will be further described with reference to the accompanying drawings.

[0020] A continuous furfural production process comprises the following steps: In the first step, the corn cob raw material is crushed by a crusher and transported to a mixer 1; In the second step, the prepared dilute sulfuric acid is sprayed into the mixer 1 by controlling the flow rate using a pump or a high-level tank according to the proportion; The third step is to stir evenly and squeeze the mixture into the hydrolyzer 3 through the feed gun 2; Step 4: After the hydrolysis is completed, the slag is discharged into the gas-slag separator 40 through the slag discharger 4, the slag collector 6, and the pressure reducing tank 5 in sequence; The fifth step is to separate the gas and slag through the slag discharge valve 7 at the bottom of the gas-slag separator 40, and the slag is transported to the warehouse through the belt, and the gas passes through the deodorization system and is discharged after being treated as qualified.

[0021] A continuous furfural production device comprises a mixer 1, wherein the discharge port of the mixer 1 is connected to a hydrolyzer 3 via a feed gun 2, the discharge port at the bottom of the hydrolyzer 3 is connected to a slag discharger 4, the discharge port of the slag discharger 4 is connected to a slag collector 6 and a pressure reducing tank 5, the discharge port of the pressure reducing tank 5 is connected to a gas-slag separator 40, and the bottom of the gas-slag separator 40 is connected to a slag discharge valve 7.

[0022] The working process of the feed gun of the present invention is as follows: The furfural hydrolysis part involves crushing corn cobs into 1-1.5 cm particles, mixing with dilute sulfuric acid (6%-7%), stirring evenly, and forcing them to squeeze (squeeze out excess water) through a piston. The extrusion section forms a certain agglomeration hardness, which can provide a certain pressure-resistant seal and a certain period of sealing. Through long-term operation, it can withstand and seal saturated steam of about 0.8 MPa. The power source is the hydraulic oil station assembly, and the oil station pressure is between 10-15 MPa. Dilute sulfuric acid is corrosive, so corrosion-resistant materials are used from the feed section, stainless steel 316L material (316L material is used for vulnerable parts; high value and difficult to repair, corrosion-resistant and hard stainless steel 321 material is used).

[0023] The feed gun can not only seal the steam pressure of 0.8MPa, but also feed continuously. When the extruded raw materials are exported, they expand rapidly, which can improve the hydrolysis yield of furfural. The extrusion sealing section can reduce the load during feeding by setting a gradually expanding pipe diameter.

[0024] The slag discharge valve of the present invention has two layers of blades, one layer of blades connected to the gas-slag separator. This design is that every time the slag is discharged, the space with stirring teeth in the gas-slag separator is larger than the space occupied by the slag discharge, and there is no dead angle stirring, and it falls freely to the lower section. The lower section is connected to the sealing belt stirring tooth function. The sealing belt stirring tooth function is a more precise processing part. The slag discharged by hydrolysis contains acetic acid, which is corrosive to ordinary steel materials. The corrosion-resistant stainless steel 316L material should be used to manufacture this equipment.

[0025] Example After the corncob is screened for impurities by a crusher (crushing particles with a diameter of about 1.5 cm), it is transported to a mixer and mixed with the prepared dilute sulfuric acid (mass concentration of about 6.8%). It is mixed at a solid (corncob) liquid (dilute sulfuric acid) mass ratio of 3:1 and transported to a feed gun. It is squeezed into the 1# hydrolyzer through a feed gun. The pressure in the 1# hydrolyzer is 0.8MPa and the temperature is 170.44℃. It moves forward through the stirring teeth (5 revolutions per minute) in the 1# hydrolyzer. The corncob stays in the 1# hydrolyzer for about 45 minutes. Through the hydrolysis reaction and friction, the corncob becomes smaller. The 1# hydrolyzer reaches the 2# hydrolyzer through a pipeline connected to the 2# hydrolyzer. The corncob is still operated by the stirring teeth in the 2# hydrolyzer, and the hydrolysis reaction and friction are performed. The corncob reaches powder and stays for about 45 minutes. It reaches the 3# hydrolyzer and the 4# hydrolyzer in turn. The total time is 180 minutes to complete the hydrolysis. The fixed slag is discharged into the slag collector through the 1# slag discharger (the slag collector is a pressure vessel, and the pressure is balanced with the hydrolyzer), and the 1# slag discharger is closed. A gravity valve is set at the top of the slag collector to automatically exhaust and reduce the pressure. When the pressure is reduced to 0.25-0.3MPa, the 2# slag discharger at the bottom of the slag collector is automatically opened, and the gas enters the gas-slag separator through the pipeline. The upper gas enters the deodorization system for discharge, and the lower gas is discharged through the slag discharge valve.

[0026] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A continuous furfural production process, characterized in that: The steps include: In the first step, the corn cob raw material is crushed by a crusher and transported to a mixer (1); In the second step, the prepared dilute sulfuric acid is sprayed into the mixer (1) by controlling the flow rate using a pump or a high-level tank according to the proportion; The third step is to stir evenly and then squeeze the mixture into the hydrolyzer (3) through the feed gun (2); In the fourth step, after the hydrolysis is completed, the slag is discharged into the gas-slag separator (40) through the slag discharger (4), the slag collector (6), and the pressure reducing tank (5) in sequence; In the fifth step, the gas and slag are separated through the slag discharge valve (7) at the bottom of the gas-slag separator (40). The slag is transported to the warehouse through a belt, and the gas passes through the deodorization system and is discharged after being treated to meet the requirements.

2. A continuous furfural production process according to claim 1, characterized in that: The corn cobs in the first step are crushed to a particle size of 1.5 cm.

3. A continuous furfural production process according to claim 1, characterized in that: The mass concentration of the dilute sulfuric acid in the second step is 6.8%, and the mass ratio of corn cobs to the dilute sulfuric acid is 3:

1.

4. A continuous furfural production process according to claim 1, characterized in that: The pressure in the hydrolyzer is 0.8 MPa, the temperature is 170° C., and the hydrolysis time in the hydrolyzer is 180 min.

5. A device for the continuous furfural production process according to claim 1, characterized in that: The invention comprises a mixer (1), wherein the discharge port of the mixer (1) is connected to a hydrolyzer (3) via a feed gun (2), the discharge port at the bottom of the hydrolyzer (3) is connected to a slag discharger (4), the discharge port of the slag discharger (4) is connected to a slag collector (6) and a pressure reducing tank (5), the discharge port of the pressure reducing tank (5) is connected to a gas-slag separator (40), and the bottom of the gas-slag separator (40) is connected to a slag discharge valve (7).

6. A continuous furfural production device according to claim 5, characterized in that: The hydrolyzer (3) comprises four horizontally placed reactors, the reactors being connected in sequence from top to bottom, the reactors being provided with conveying stirring blades, the stirring blades being connected to a power rotating assembly, sealing assemblies and bearing brackets being provided at both ends of the reactors, and the reactors being equipped with a radar level meter.

7. A continuous furfural production device according to claim 6, characterized in that: Six sets of steam control valves are installed at equal intervals at the lower part of the reactor, and a steam and raw material intersection section and an aldehyde outlet are arranged at the top of the uppermost reactor.

8. A continuous furfural production device according to claim 5, characterized in that: The feed gun (2) comprises a cylinder barrel (8), wherein the cylinder barrel (8) comprises a travel section, a feed section and an extrusion sealing section in sequence; a travel switch (9) is provided on the outer side of the travel section of the cylinder barrel (8), a feed port (10) is provided on the top of the feed section of the cylinder barrel (8), and a preheating sleeve (11) is provided on the outer side of the extrusion sealing section of the cylinder barrel (8); a piston (12) is provided in the cylinder barrel (8), one end of the piston (12) is connected to an oil cylinder (13), and the other end of the oil cylinder (13) extends out of the cylinder barrel (8). On the outside, a limiter (14) is provided on the oil cylinder (13), and one end of the limiter (14) passes through a travel switch (9); an end of the cylinder barrel (8) close to the extrusion sealing section is provided with a discharge port (15), and the discharge port (15) is connected to the feed port of the reactor; the oil cylinder (13) and the piston (12) are connected by a thread; one end of the oil cylinder (13) is connected to a hydraulic oil station for providing a power source; and the inner diameter of the extrusion sealing section of the cylinder barrel (8) is gradually expanded toward the discharge port (15).

9. A continuous furfural production device according to claim 5, characterized in that: The slag discharger (4) comprises a second cylinder barrel (16), wherein a second piston (17) is arranged inside the second cylinder barrel (16) and moves along the second cylinder barrel (16), one end of the second piston (17) is connected to a second oil cylinder (19) via a connecting rod (18), a second limiter (20) is arranged on the connecting rod (18), a second travel switch (21) is arranged at the top end of the second cylinder barrel (16) on the side close to the second oil cylinder (19), the second limiter (20) passes through the second travel switch (21), and a second feed port (22) is arranged at the top end of the second cylinder barrel (16) on the side away from the second oil cylinder (19), and the feed port (22) is provided. Port 2 (22) is connected to the discharge port of the reactor, a slag discharge port (23) is provided at one end of the cylinder barrel (16) away from the oil cylinder (19), and the slag discharge port (23) is connected to the pressure reducing tank (5), a sealing section is provided in the middle of the cylinder barrel (16), and an exhaust port (25) is provided near the top of the sealing section of the cylinder barrel (16), and the exhaust port (25) is close to one side of the slag discharge port (23), the connecting rod (18) and the piston (17) are connected via a fixing frame (26), and a hydraulic oil station for providing power is provided at one end of the oil cylinder (19).

10. A continuous furfural production device according to claim 5, characterized in that: The slag discharge valve (7) comprises a blade cylinder (27), wherein an upper blocking plate (28) and a lower blocking plate (29) are respectively provided in the middle and at the bottom of the blade cylinder (27), wherein the upper blocking plate (28) and the lower blocking plate (29) are respectively provided with openings, a rotating shaft (30) is passed through the center of the blade cylinder (27), a blade (31) is provided on the rotating shaft (30), a sprocket (32) is provided at the portion of the rotating shaft (30) located at the bottom of the blade cylinder (27), and the sprocket (32) is connected to a motor via a chain, the number of blades (31) located at the upper portion of the upper blocking plate (28) of the blade cylinder (27) is four, and they are arranged alternately, and the number of blades (31) located at the lower portion of the upper blocking plate (28) of the blade cylinder (27) is two, and they are arranged relative to the rotating shaft (3 0) are symmetrically arranged, the openings of the upper blocking plate (28) and the lower blocking plate (29) are symmetrically arranged, and the size of the opening does not exceed the size of one blade, the portion of the rotating shaft (30) located on the upper blocking plate (28) is provided with a shaft sleeve bracket (33), a nylon sleeve is provided in the shaft sleeve bracket (33), and a blade fixing frame (34) is provided at the top of the shaft sleeve bracket (33), the rotating shaft (30) is located at the bottom of the blade cylinder (27) and is connected to a bearing (36) through a bearing bracket (35), a stuffing box (37) is provided in the bearing bracket (35), a dust shield (38) is provided at the bottom of the bearing (36), and the dust shield (38) is sleeved on the rotating shaft (30), and a flange (39) for connection is provided at the top of the blade cylinder (27).

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